eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!

[EEVblog]

3% of Tesla Solar Panels on Walmart stores are CATCHING ON FIRE! 

[G7PSK]

It says in the text Dave was going through that Walmart says there was another fire after Tesla turned the systems off.

[orion242]

The panels match their cars.

Maybe they should bundle in a fire extinguisher with any Tesla purchase.

They also claimed they where not grounded properly, serviced by clueless techs and high number visible defects where ignored.

https://www.cnbc.com/2019/08/20/walmart-sues-tesla-over-solar-panel-fires-at-seven-stores.html

Rental solar or rental house fire??

[nctnico]

It says in the text Dave was going through that Walmart says there was another fire after Tesla turned the systems off.

Well... how do you turn a solar panel off? With a large array of solar panels there is a lot of power involved so obviously there is a risk of fire. If the wiring is flaky and causes a short (not saying that this is the case) then you have a problem on your hands.

[SilverSolder]

"Nothing's so good it's not bad for something" ...    as the saying goes.

As the industry matures,  the safety will no doubt improve.  It might never get better than current mains electrical systems, though...   which can and do cause fires every day!

Highlights from a US National Fire Protection Association (NFPA) report:

Electrical failures or malfunctions were the second leading cause of U.S. home fires in 2012-2016 (behind fires caused by unattended equipment), accounting for 13% of home structure fires.

Fires involving electrical failures or malfunctions accounted for the highest share of civilian deaths (18%) and direct property damage (20%).
Nearly two of five fires (39%) involving electrical failure or malfunction occurred in the cold weather months from November through February.
Arcing was the heat source in approximately three of five home fires involving an electrical failure or malfunction.
Electrical distribution and lighting equipment was the third leading form of equipment involved in fires in U.S. homes in 2012-2016, accounting for 10% of fires (behind cooking equipment and heating equipment).

Non-confined home fires involving electrical distribution and lighting equipment most often originated in a bedroom (17% of total), attic or ceiling (12%), or a wall assembly or concealed space (9%).
Approximately one-quarter (24%) of these fires occurred between midnight and 8 a.m., but these fires accounted for 60% of deaths.

[orion242]

Well... how do you turn a solar panel off?

Didn't they tarp over the solar roadway in Germany that caught fire?

[EEVblog]

It says in the text Dave was going through that Walmart says there was another fire after Tesla turned the systems off.

Yeah, missed that. Definite internal panel fault, also confirmed in another article

[EEVblog]

Well... how do you turn a solar panel off?

Didn't they tarp over the solar roadway in Germany that caught fire?

I tarped over mine when it failed until I could get it fixed.

[SeanB]

Makro here in South Africa have put solar panels on all the parking, to provide shade and power. Because of the heat the inverters also have by them a pair of big 45cm diameter industrial fans, running 24/7, to provide extra cooling for the inverters. Inverters are in a corner, with a roof and a fence to keep them safe, and the fans are bolted to the tar of the parking bay this originally was. Have not seen any fail so far, and they have been there for nearly 2 years now, probably already paid off the cost of the panels in power savings as well.

Panels themselves are a Chinese made one, installed and maintained by a South African company, who specialise in turnkey solar installations, and also who do rent to own solar arrays, as there currently is no legislation allowing you to have grid tied panels and feed power back into the grid (thank you for the state owned failopoly of ESKOM, currently billions of dollars in the red due to reasons, and who the rest of the taxpayers have to bail out again and again) legally, though there are plenty of smaller systems around doing peak shaving.

Like Martin Lorton, having battery backed solar to provide lower cost power and a more reliable grid. There are some municipalities that do allow grid tie, at a ridiculously low rate, equal to the cost they pay off peak, but with a rather high fixed charge per month, along with limits on power allowed to be fed back as well.

For those looking for DIY solar panels, and DC arcing with even a low (60VDC) panel array, look at Kreosan with his home made panels here. Ukranian, but if you can understand Dave you can understand him in English.

[Alex26641]

McFly1   VERY good one!  Regards, Alex

[edavid]

3% of Tesla Solar Panels on Walmart stores are CATCHING ON FIRE! 

That should be "Tesla solar panels on 3% of Walmart stores where they were installed ...".  Big difference.

[bdunham7]

It says in the text Dave was going through that Walmart says there was another fire after Tesla turned the systems off.

Yeah, missed that. Definite internal panel fault, also confirmed in another article

One of these was near me (Riverside) and I've been looking for more info, but not getting anything substantial.  I realize the panels burned, but how do they know it was a panel fault specifically?  And is there any info on which panels they were using?

[bdunham7]

Well... how do you turn a solar panel off?

Use microinverters.  Then they are as off as they get.

[bdunham7]

3% of Tesla Solar Panels on Walmart stores are CATCHING ON FIRE! 

Dave, you asked about HV strings in the US.  Microinverters (and the SolarEdge optimizer alternative) are common, but not required.  I think they should be required for installations on buildings, but HV installations are still used, especially in large commercial.  It's just a bit cheaper.  I believe very large installations like the burning Walmart ones actually use HV strings of 500V+ and then put those strings in parallel so they can have fewer wiring runs.  I really want to see how these things were set up, but I doubt anyone is racing to make that public.  You can imagine that if they had say 8 12-panel strings in parallel without adequate protection or blocking, that a small fault in one system could be backfed by the other seven with great incendiary effect.

My guess is that Walmart's suit has stated it correctly.  They did a piss-poor job.  Can anyone tell by looking what panels those are?

[Marco]

Not really Tesla's panels, they just bought into the liability.

I wonder if standardizing on a HF AC distribution network with capacitive coupling wouldn't be better than micro-inverters.

[maginnovision]

Tesla bought solar city entirely, they're Teslas panels even if the panels have changed since those were produced. Same as any producer the products change over time I highly doubt the buyout affected much of anything in terms of lifecycle.

[gardner]

Dave mentioned the Tesla truck.  I couldn't help myself digging up some stuff I posted to the Canadian Money Forum in the Tesla thread after they announced the electric HGV....

An average loaded semi runs around 36L of diesel/100km. Diesel contains about 10 kWh/L and current diesel semis are about 50% efficient so that's 180 kWh/100km or 1,460 kWh for the 800 km range the tesla truck is meant to have. Tesla's newest batteries have a claimed capacity of 0.25 kWh/kg (though the specs on the new powerwall work out to closer to 0.1 kWh/kg) and using this optimistic figure gives us about 5,800 kg of batteries. This is not a preposterous number, but given a semi tractor is around 13,000 kg and only 1,200 kg is engine, that is a good deal of extra weight to be carrying around.

Recharging a 1,460 kWh pack by 50% in 30 minutes requires 1,500 kVA of power. A 1,500 kVA transformer is one of those jobs the size of a van generally sized to supply about 1,200 homes. A facility that could charge more than one of these semis would be a pretty big deal. Not every industrial installation would have this sort of capacity on site.

Maybe Tesla can make a go of it, but I am a bit skeptical. If I were an investor, I would want them to priorize model 3 delivery and profitability above this truck business. Daimler/Fuso/Mitsubishi is ahead of them already and trying to close ground on them would be a substantial distraction.

* Diesel trucks waste energy when they hit the brakes. Electric trucks waste very little while braking.

The fuel figure I used was a highway driving one -- there would be comparatively little other than simply cruising in that. Semi-trucks generally spend 99% of the time cruising at a constant speed. Sure regenerative braking could help, but it's going to be a 1% thing, not a factor of 4 thing.

* Vehicle batteries are not the same as the energy storage business batteries.

The 0.25 kWh/kg is what they claim for the current custom 18650 battery cells produced by Panasonic. Maybe the ones they would use will have a higher density. I can't find any specific claims from Tesla, but commercial 21700s that are available seem to run around 280 Wh/kg -- a bit better, but not a night/day thing.

* As for anyone being ahead of Tesla in the semi space

I never said semi tractor -- I said truck. The Daimler/Fuso/Mitsubishi truck is a smaller 5t panel van style truck, not a 36t semi rig. It has ~1/4 the range and ~1/8 the weight and consequently a much smaller battery requirement. They claim to have them in commercial service -- seems mostly in Germany. They are building real experience in this space and I would not want to discount it.

[orion242]

Doesn't sound like its the panels so much as the half arsed install and maintenance by Tesla that Wally world is complaining about.

Looks like a fair bit of Wallys filing with the court is redacted or otherwise hidden from the public eye, but there is a ton of reading material that is available on the net here

http://iapps.courts.state.ny.us/iscroll/SQLData.jsp?IndexNo=654765-2019

Looks like I can't do a direct link, but just enter the captcha and search for Tesla.

[orion242]

Exhibit 252

"The Letter's assertion that Walmart has continued de-energization of 244 systems "based on events that occurred at four" (id.) is incorrect: Walmart has inspected numerous sites (beyond the four that experienced fires in 2018), and the results of its examinations—coupled with the conclusions of Tesla's own inspectors—confirmed that conditions creating a risk of fire were present at site after site. Tesla's inspection reports, far from reassuring Walmart that the sites are safe, have increased Walmart's concerns by further documenting patterns of negligence by Tesla. Tesla's cavalier dismissal of those findings—and its suggestion that Walmart should re-energize sites that Tesla's own inspectors found to pose safety risks—reflects either an inability to appreciate its inspectors' findings or indifference towards the safety of Walmart's personnel and customers"

Gonna have to grab a cold drink and popcorn and take a read though all this...

[floobydust]

I'm wondering if the solar panels and wiring have significant inductance.  Enough to sustain a DC arc that etches across the solar cells? Or is it a ground fault.
There seems to be nothing that can interrupt the arc- a thermal fuse or AFCI for the purpose.

(I posted this question in Solar and Renewable thread not realizing discussion is here)

The pic is from the court filing.

[orion242]

"Walmart has no right, contractual or otherwise, to de-energize 244 systems based on events that occurred at four.  Likewise, Walmart does not have the right to keep any of those systems de-energized indefinitely while it makes extra-contractual demands and refuses to even look at the systems that Tesla has inspected.The only basis that Walmart has offered for doing so is its assertion that each and every one of the 248 sites poses an imminent risk to safety or property.  In fact, there is no factual basis for claiming that there is an imminent risk to safety or property, and Walmart cannot make that claim in good faith while it steadfastly refuses to actually look at the systems that sit idle on the rooftops of Walmart’s own stores"

You don't have the right to turn them off over a few fires...  Telsa's lawyer goes on to say...

"Walmart demanded, which you describe as “reasonable,”would have made Tesla liable for thermal events even if they were not caused by the Tesla system; an especially untenable demand given that there are reported fires at Walmart stores on a nearly weekly basis that have nothing to do with solar systems.)"

Your stores are burning all the time, big deal...

[orion242]

Well... how do you turn a solar panel off?

Didn't they tarp over the solar roadway in Germany that caught fire?

I tarped over mine when it failed until I could get it fixed.

And from the sounds of exhibit 245 exactly what wally world wanted

"Tesla shall de-energize all solar panels so that no AC or DC power is generated and suspend solar operations at all of the Affected Sites immediately, but in no event later than June 30, 2018"

[floobydust]

"...Walmart attorneys allege SolarCity raced to install solar panels as quickly as possible with haphazard precautions and inadequate safety practices before its acquisition. When Tesla took over, Walmart says the company was ill-equipped to manage and install solar panels and correct mistakes of its subsidiary. Among the allegations: Tesla failed to properly “ground” the systems to decrease the risk of fire. Inspections revealed numerous deficiencies, including exposed, hanging and frayed wires susceptible to arcing, where electricity deviates from its intended path, creating a fire risk."

Tesla energy division revenue $368 million Q2 2019. They must be getting money from the Walmart rooftop systems which is why they don't want them turned off.

[orion242]

Exhibit 248

Beaver creek Ohio Fire(March7.2018):

"For example, Walmart understands that improperly sealed housing during installation permitted water intrusion into the Fronius inverter, which likely contributed to the fire's ignition.  Moreover, brass/metal bolts were used in the inverter fusebox(rather than fuses as required by both the Fronius manual and the National Electric Code)"

Bolts for fuses!    WTF!?!

Also blames the same inverter in another case and piss poor install maintenance on a third site.

Same exhibit

At Yuba City, CA, Walmart claims the system was de-energized by Telsa and showed signs of a fire after this with wires arcing at the time of discovery by Walmart.  Tesla who is apparently monitoring these installs, got ground fault alerts between June 5 & September 11 2018 and failed to act or alert Walmart of the condition.      On the bright side, at least it was grounded in some fashion!!

248 also contains observations by Wallyworld's own consultant inspecting these systems.  So far the best read.

249 has some interesting bits.

-Almost all the sites are 2016 and older, when Musk's cuz was installing these under solar city.
-Tesla also claims loss of power generation has cost them at least $13.7M and $37.4K per day.
-A list of recent non-solar store fires Tesla points out.  $hit happens, man....
-Seems to state most of Tesla's issues with Wallyworld

[themadhippy]

Bolts for fuses!    WTF!?!

[orion242]

I'm wondering if the solar panels and wiring have significant inductance.  Enough to sustain a DC arc that etches across the solar cells? Or is it a ground fault.
There seems to be nothing that can interrupt the arc- a thermal fuse or AFCI for the purpose.

(I posted this question in Solar and Renewable thread not realizing discussion is here)

The pic is from the court filing.

There we go.  Was looking for some pics, its the bottom link of exhibits.  Somewhat disappointed wallyworld held back the fuse box with bolts.  You can bet your arse they have it.

I'm pretty impressed that the roofing materials seem fairly fire resistant.  Would have thought what looks like standard commercial rubber roofing with urethane based insulation under would have spread fire easily.  Wonder if they have any hot tar roofs with Tesla solar?

[David Hess]

I'm wondering if the solar panels and wiring have significant inductance.  Enough to sustain a DC arc that etches across the solar cells? Or is it a ground fault.

The voltage versus current curve of a photovoltaic source makes it self ballasting so no inductance is required.  They operate more as a constant current source under arcing conditions.

My guess is that environmental contamination causes electrolysis which eventually leads to arcing.

(I posted this question in Solar and Renewable thread not realizing discussion is here)

I did the same thing.

[orion242]

My guess is that environmental contamination causes electrolysis which eventually leads to arcing

I suspect the high paid ($600K for 248 sites) cheap consultants hired by Wally nailed it.  Almost all their points are related to a piss poor install that hasn't been maintained let alone inspected for some time.  What service was done, was by poorly trained individuals.  Wally claims one of Tesla's people was spotted walking on the panels.    Tesla cannot provide a single inspection report prior to 2018 according to this as I recall.  Sounds like inspections didn't start till after the first fire.  Slap them in, don't bother to do the maintenance/inspection your under contract for and hope it all shakes out till things become profitable...then "make it right" maybe...  Oh wait, the dick that did this cashed out and Musk bought this turd.

Lawyers will be fighting it out for a few years now, but it sure smells like a stinker.

[bdunham7]

I've been reading through the exhibits, but I can't find anything the tells me what Tesla identified as the 'root cause' of the two fires that Walmart acknowledges that they have finally coughed up their analysis.  And these were all roof fires, if I understand, but they blame the inverter?  Are the inverters installed on the roof in this setup--anyone know?

[orion242]

Wally want's Tesla to issue a final root cause report on each site with a fire, and they claim Tesla has not ever provided them with one.

Read exhibit 248 bottom of page 6 and down for Tesla's inspection of ~30/248 sites as reported by wally.

[EEVblog]

Not really Tesla's panels, they just bought into the liability.

And it seems failed to rectify known issues after the acquisition in 2016

[orion242]

Failed on known issues?  They apparently ignored GF alerts after several fires??  AFTER wally orders in writing to stop all AC/DC generation.  HELLO MCFLY!  Under contract for maintenance and operation?

They didn't start inspecting them till after fires in 2018 at the request of wally and they sound to be under contract to do regularly.  What's regularly is grey, but I'm guessing industry standards that wally can point to are going to narrow more than one every two years.  They also don't seem to be able to document they have ever been inspected which goes back to at least 2012 or further.  Show a court there its not industry standard to put eyes on an install in 5+ years under a kind of performance contract as this sounds, good luck.  You can also bet wally is going to go after the likely fact few Tesla representatives touching these systems held licenses/qualifications required by the respective AHJ.  Would also add that Tesla also calls out that these systems where inspected by the AHJ at the time of install and approved.  That's fine and dandy.  Final inspection approval by the AHJ does NOT absolve one from liability of a code violating install.

[bdunham7]

Wally want's Tesla to issue a final root cause report on each site with a fire, and they claim Tesla has not ever provided them with one.

Read exhibit 248 bottom of page 6 and down for Tesla's inspection of ~30/248 sites as reported by wally.

Exhibit 252 p 2

" In fact, Walmart did not see any final root cause analyses
until August 8, 2019, when-over fourteen months after Walmart's initial request-Tesla finally
produced the first of these reports. The rest remain outstanding. "

I seem to remember a reference to there being two completed "root cause" reports.  No mention of what is in it or them.  I'd really like to hear Tesla's explanations for the fires that we do know actually happened.

[orion242]

I seem to remember a reference to there being two completed "root cause" reports.  No mention of what is in it or them.  I'd really like to hear Tesla's explanations for the fires that we do know actually happened.

Exhibit 245

use search for "root cause" seems to be the first.  Dated May 31, 2018

Wally brings this up in many of the provided exhibits that all appear to be between legal teams.  There are mentions of calls as well between both parties, but of course there are no transcriptions of those here.  Wally want a root cause of all fires, and Tesla has not provided that.  Can't provide a detailed cause of each fire to date, show its mitigated in all 248 installs, the $hit remains off seems to be wally's response in a nut shell.  They also want damages for each fire directly tied to these installs, and Tesla to assume any further fire damages added to their 248 contracts on the installed systems.  Yep insanity, each install seems to be a separate contract.  Lawyers wet dream & design apparently.  Both parties seem to agree language is basically the same between them all.

[bdunham7]

Exhibit 245

use search for root case seems to be the first.  Dated May 31, 2018

Wally brings this up in many of the provided exhibits that all appear to be between legal teams.  There are mentions of calls as well between both parties, but of course there are no transcriptions of those here.  Wally want a root cause of all fires, and Tesla has not provided that.  Can't provide a detailed cause of each fire to date, show its mitigated in all 248 installs, the $hit remains off seems to be wally's response in a nut shell.  They also want damages for each fire directly tied to these installs, and Tesla to assume any further fire damages added to their 248 contracts on the installed systems.

Yes, I keep seeing "root cause" mentioned,  but not even a hint of what Tesla may have found.  I suspect what is going on here is that there isn't a single, consistent or even well-established caused for the various fires, so Walmart is not claiming any specific defect, but rather that Tesla just made so many errors that they were negligent in general.  That's actually a harder case to make, b/t/w.   Unless there are bolts in the fuse holders and corrosion damage from missing covers.....

[orion242]

but not even a hint of what Tesla may have found.

Did you bother to read wallys summery of Tesla's reports on ~30 sites?  Few posts above I call out exactly where wally documents ~30 of Tesla's own inspection reports calling out safety issues in 50% of them and action items on nearly all of them.  That's 30 sites of 248.

Again this is just court docs filed by wally.  Time will tell, good luck Tesla I'm sure wally is just tossing their weight around.

Edit - Your correct, do believe there is reference of one or two "root cause" reports but they are not in what's available in these exhibits.  Given wallys account of the three fires they do talk about and their summery of Tesla's own reports, it all looks like initial install issues.  They specifically point to the inverters twice, one with bypassed fuses and water leaks.

[EEVblog]

Great research here, Tesla are big-time to blame here:

[maginnovision]

I'm not going to subscribe to his channel, but that's a good video.

[f4eru]

Wally claims one of Tesla's personally was spotted walking on the panels. 

Who new Tesla was into Solar Walkways

[orion242]

Good video, sums it up nicely.

I think at this point there is a snowballs chance in hell wally would allow Tesla to preform any work on these sites.  More likely wally will want to hire their own contractor to remove/replace all these installs and hand the bill to Tesla.

[EEVblog]

Good video, sums it up nicely.
I think at this point there is a snowballs chance in hell wally would allow Tesla to preform any work on these sites.  More likely wally will want to hire their own contractor to remove/replace all these installs and hand the bill to Tesla.

Was hilarious how the Tesla lawyer practically begged for the lawsuit  :-//a

[orion242]

Ya....  your stores are constantly on fire, big deal.

What an arrogant ahole response to seven fires all directly related to their equipment.   

Wonder how many other Tesla installs are of the same quality.  Might be a wad of pending lawsuits from resi installs that don't make the news or settle quietly.

[bdunham7]

Great research here, Tesla are big-time to blame here:

So, here's the same guy just a few days before....
b/t/w, his advice in this video is aimed at his (and my) locale of Southern California.  And he's pretty much spot on until he starts to wax eloquent about how great Tesla is...

[bdunham7]

Ya....  your stores are constantly on fire, big deal.

What an arrogant ahole response to seven fires all directly related to their equipment.   

Wonder how many other Tesla installs are of the same quality.  Might be a wad of pending lawsuits from resi installs that don't make the news or settle quietly.

Take it from me, the tone and substance of Tesla's reply is 100% driven by the client. 

Judging by Yelp reviews and the consistency of the complaints (my roof leaks, the system doesn't work, they lied about the costs/terms, they don't answer the phone), I'm going to guess that they are design thrifted, subcontracted to the lowest bidder and on to the next.

[floobydust]

This turd smells like the solar roadways - it's subsidies, politics, lease/loan/purchase power agreements and business deals that have nothing to do with reality.

Panels from Trina and Yingli solar china, $0.75B state subsidies to SolarCity who is $2.9B in debt 2016, Tesla buyout for $2.6B as investors complain amidst serious conflicts of interest.

US Trade ruling and Trump order added tariffs 30% (-5%/year) on imported solar cells and modules. You can't wave a magic wand and expect to hire thousands and be producing solar cells in America, especially when china produces 71% of the world's panels and 60% of the world's solar cells.

I think Gigafactory 2 in Buffalo NY, "producing" solar roof tiles, it was Panasonic imported cells and not sure if they actually make any of the cells yet in NY. Musk demo'd the glass shingles that couldn't even produce electricity. An ounce of image is worth a pound of performance.

All the SolarCity installations look very shoddy, plenty of youtube vids that show a rushed, inexperienced crew, as if plumbers did the work.
I think the back sheet/laminate on the module is a little too flammable and only 90C 12AWG wire.
Fuses are Trina recommended (to 20A) only to protect the reverse-diodes, they do not seem to be for anything else.

https://www.bloomberg.com/news/features/2018-11-20/inside-elon-musk-s-forgotten-gigafactory-2-in-buffalo

[David Hess]

This turd smells like the solar roadways - it's subsidies, politics, lease/loan/purchase power agreements and business deals that have nothing to do with reality.

I agree in the sense that most or many renewable and green energy initiatives are rent seeking scams.  But at least rooftop solar, unlike solar roadways, can work without violating mechanical engineering.

[maginnovision]

Great research here, Tesla are big-time to blame here:

So, here's the same guy just a few days before....
b/t/w, his advice in this video is aimed at his (and my) locale of Southern California.  And he's pretty much spot on until he starts to wax eloquent about how great Tesla is...

I saw that same video and was surprised he was around here too and not saying that everyone everywhere should get the biggest solar system they could afford. He also had a decent video on solar "scams" going into issues with certain contracts and types. It seems his opinion on Tesla started moving pretty quick with this lawsuit business. Owning a Tesla however I'm sure he'll reconcile pretty quickly.

[orion242]

Owning a Tesla however I'm sure he'll reconcile pretty quickly.

Not just the car, a fair wad of stock.  Not sure I could sleep after tossing that kind of money at a company operating as long and with constant losses.  Its a religion apparently.  If you believe hard enough, it will happen.

[floobydust]

Amphenol H4 PV connectors are being implicated, there's now calls to have Musk resign, as "Last year, Tesla initiated 'Project Titan' — a stealth nationwide program to replace solar panel parts that could cause fires".... "a remediation effort to limit any impact the [H-4] connector may have had."

TBH the H4's look not so great- special crimp tool, strip tool, unlock tool, wrench tool etc. which installers would likely never have. And only one tiny seal ring for IP68. I'm not sure how it seals against the wire(end) or what OD it can accommodate. Automotive connectors are much better, less complicated - triple seal rings too, just need a HV rating. Trina Solar switched over to their own proprietary TS4 connector.

I'd guess the installers did hasty crap-ola assembly/crimp of the H4's.

edit: youtube videos on assembling these looks straightforward- with the special tools. But your IQ must be over 50.

[bdunham7]

https://www.renvu.com/Learn/MC4-VS-H4-Multi-contact-MC4-Compared-To-Amphenol-H4

I'm sure Walmart's lawyers are trotting out every complaint they can, regardless of of what caused the fires.  "Mismatched" connectors are a different (regulatory, according to the link) problem than piss-poor installation and crimping by untrained installers without proper tools--if that's what happened.

[floobydust]

Specialty tools I never see people have them on the jobsite. These are general labourers doing the work.
Amphenol H4 crimping tool H4TC003 is $500, they are expensive so I would expect installers to improvise... unless their employer supplies hand tools.

Is there some irony here, Walmart sells MC4 connectors https://www.walmart.com/c/kp/mc4-connectors

[bdunham7]

https://www.solaris-shop.com/amphenol-helios-pv-670508-000-h4-crimp-tool/

And I'm not sure the MC4 tool wouldn't work fine, although not approved by Amphenol of course...

https://www.amazon.com/BougeRV-Solar-Crimping-Tools-2-5-6-0mm%C2%B2/dp/B07C2N6CKM/ref=pd_cp_86_4?pd_rd_w=4wjF1&pf_rd_p=ef4dc990-a9ca-4945-ae0b-f8d549198ed6&pf_rd_r=0NETK989GE0ZNN1WTH3F&pd_rd_r=a84bc074-a939-4589-88f5-2fcc128f237d&pd_rd_wg=XcVL6&pd_rd_i=B07C2N6CKM&psc=1&refRID=0NETK989GE0ZNN1WTH3F

Plus another $5 for the wrenches.

Not having the necessary tools is pathetic, for a professional installer company not to have them is criminal (literally in some cases...).  There isn't a single field-installed connector anywhere on my roof, but if there was, the proper tools would have been used even if I had to buy them myself for one use.

[G7PSK]

Don't know about the US but here in the UK solar panels come with the Amphenol plugs already fitted. I have not heard of them catching fire here, but then we don't have California sun. Must one thing though whenever I have fitted solar panels I have cut the Amphenol plugs off and replaced them with Powerpole, That is because I have only ever put solar panels on vehicles in order to charge batteries for radios.

[David Hess]

Don't know about the US but here in the UK solar panels come with the Amphenol plugs already fitted. I have not heard of them catching fire here, but then we don't have California sun.

California has more sun in the UK but the solar insolation is no greater because of all of the proposition 65 stickers stuck to the front of the solar panels.

[G7PSK]

Don't know about the US but here in the UK solar panels come with the Amphenol plugs already fitted. I have not heard of them catching fire here, but then we don't have California sun.

California has more sun in the UK but the solar insolation is no greater because of all of the proposition 65 stickers stuck to the front of the solar panels.

Every thing in California is known to cause cancer,which is why I am glad I don't live in California, I can bath in all these noxious substances with impunity safe in the knowledge I wont get cancer.

[orion242]

TBH the H4's look not so great- special crimp tool, strip tool, unlock tool, wrench tool etc. which installers would likely never have.

Looks fiddly, but they likely to need similar with most of the DC connectors I have seen on panels.  I wouldn't suspect those cheap plastic wrenches to last a wally scale install. 

I'm not sure how it seals against the wire(end) or what OD it can accommodate.

Has to be that white rubber grommet.  The ferule compresses it as you tighten the nut down.  If hand tight, water surely is getting in which is just a matter of time then.

Has there been problems with this specific connector?  Why rush to replace them if not?

[orion242]

Don't know about the US but here in the UK solar panels come with the Amphenol plugs already fitted.

See many with whatever connector also factory fitted.  They may be field assembling the longer runs from the panels to the inverters and mating with the factory assembled connectors on the panels.  If they are series strings, at some point your + & - need to get back together.

If the same person walking on the panels is in charge of crimping...  Using pre-made 25, 50, & 100' cables might be a better option.

I'm surprised Wally is going to work with Tesla now to correct these.  Bet that's going to be miserable for that team.  Wonder if Telsa's lawyer is keeping the non-solar store fire list current or back to public defender.

[David Hess]

I'm not sure how it seals against the wire(end) or what OD it can accommodate.

Has to be that white rubber grommet.  The ferule compresses it as you tighten the nut down.  If hand tight, water surely is getting in which is just a matter of time then.

That is exactly how it works.  There is a cable gland inside the connector which compressed against the surface of the cable.  With care these are suitable even in washdown environments but drip loops should still be used.

Has there been problems with this specific connector?  Why rush to replace them if not?

They might figure that the cost of replacement is no worse than the cost of inspection and then replacement if necessary.  Improper installation which seems likely at this point could have left the cable glands damaged anyway.

[orion242]

That is exactly how it works.  There is a cable gland inside the connector which compressed against the surface of the cable.  With care these are suitable even in washdown environments but drip loops should still be used.

Looks fairly solid to me.  Just surprised they would rush to remove them with something else unless there was/are real issues with them.

They might figure that the cost of replacement is no worse than the cost of inspection and then replacement if necessary.  Improper installation which seems likely at this point could have left the cable glands damaged anyway.

Agree.  They may have switched connectors because the new ones require a lower IQ to install.  Labor pissed off either way.  Inspect, make a call (which wally will claim is wrong 25% of the time requiring a return trip) vs just replace all.

Even the MC4 connector uses cheap plastic wrenches to tighten?  Seems to be fewer parts, but its going to need a good tighten to seal properly and the factory tool is crap.  Handful of uses, sure.  100+ panels, plastic wrenches???  Asking for problems IMO.

I would love to know what "plumbing tool" exactly was referenced being used and if that had anything to do with the connectors.  Whatever it is, has to make a good story.

[orion242]

Still, the panels have XYZ connector factory supplied.  To replace all likely means field modifying that termination.  Doing so assumes some liability of that connection that shouldn't be.  The panel warranty is almost certainly done if you wack off the supplied connection.

There has to be more to the connector story.

[madires]

Tesla working to resolve dispute with Walmart over solar panel fires
https://arstechnica.com/tech-policy/2019/08/tesla-working-to-resolve-dispute-with-walmart-over-solar-panel-fires/

My guess is that Walmart tried to talk to Tesla before the lawsuit and Tesla declined.

[oPossum]

"On Friday, Amazon.com Inc. said a June 2018 blaze on the roof of one of its warehouses in Redlands, California, involved a solar panel system that Tesla’s SolarCity division had installed. The Seattle-based retail giant said by email that it has since taken steps to protect its facilities and has no plans to install more Tesla systems."

https://www.bloomberg.com/news/articles/2019-08-23/amazon-joins-walmart-in-saying-tesla-solar-panels-caught-fire

[maginnovision]

"On Friday, Amazon.com Inc. said a June 2018 blaze on the roof of one of its warehouses in Redlands, California, involved a solar panel system that Tesla’s SolarCity division had installed. The Seattle-based retail giant said by email that it has since taken steps to protect its facilities and has no plans to install more Tesla systems."

https://www.bloomberg.com/news/articles/2019-08-23/amazon-joins-walmart-in-saying-tesla-solar-panels-caught-fire

Don't worry, Electrek, teslarati, or cleantechnica or whoever will let you know what REALLY happened soon.

[bdunham7]

Even the MC4 connector uses cheap plastic wrenches to tighten?  Seems to be fewer parts, but its going to need a good tighten to seal properly and the factory tool is crap.  Handful of uses, sure.  100+ panels, plastic wrenches???  Asking for problems IMO.

I would love to know what "plumbing tool" exactly was referenced being used and if that had anything to do with the connectors.  Whatever it is, has to make a good story.

You can go pro and get the twice-as-expensive metal MC4 wrenches...

https://www.amazon.com/Sunway-Solar-Connectors-Wrenches-Assembly/dp/B01MT9UEYH/ref=pd_lpo_sbs_86_t_1?_encoding=UTF8&psc=1&refRID=395VYTHP2H0X3Y2RPT1A

The "plumbing tool" was probably channel lock pliers...

[bdunham7]

This article is good, but scroll down for the pictures!  Lots of them!

http://www.acsolarwarehouse.com/news/solar-fires-dc-arc-faults-on-solar-systems/

[David Hess]

I would love to know what "plumbing tool" exactly was referenced being used and if that had anything to do with the connectors.  Whatever it is, has to make a good story.

Tongue and groove pliers would be my first guess.

I assume the connector housings have a torque specification to properly compress the cable gland but I do not know anybody who used a calibrated wrench.  Maybe that explains the high price for the official tool?

I have installed similar connectors before and learned how much to tighten them by testing for leaks.

[floobydust]

Tesla is faulting Amphenol. It's a typical trainwreck with Amphenol being so complicated and obtuse with their datasheets and part numbers, no dates or revision numbers, across seven corporate divisions. It's hell to find datasheets, install instructions, tools etc. There is a coded part number and ATS china part number.

H4 PV and new H4 UTX connectors total four different pins: stamped-and-formed or cold-formed (machined w/Radsok insert), and each needs a different crimp die, and not clear which pins are compatible.  I found over ten crimping tools out there, some obsolete for some reason.
The back cap (cable gland) must be torqued between 2.6 and 2.9N⋅m, let me get my magic cable gland torque wrench for that.

These connectors are too complicated for average Joe to properly assemble- the tools/pins are terribly documented.  Connectors are under the panel so for many you'd have to unmount every panel to get access for replacing them, very labour intensive.

Can't they do a IR thermal cam scan and look for hot spots, something preemptive ?

[Bud]

Tesla is not an average Joe. They what, were unable to reach Amphenol for proper information?

[bdunham7]

Tesla is faulting Amphenol. It's a typical trainwreck with Amphenol being so complicated and obtuse with their datasheets and part numbers, no dates or revision numbers, across seven corporate divisions. It's hell to find datasheets, install instructions, tools etc. There is a coded part number and ATS china part number.

H4 PV and new H4 UTX connectors total four different pins: stamped-and-formed or cold-formed (machined w/Radsok insert), and each needs a different crimp die, and not clear which pins are compatible.  I found over ten crimping tools out there, some obsolete for some reason.
The back cap (cable gland) must be torqued between 2.6 and 2.9N⋅m, let me get my magic cable gland torque wrench for that.

These connectors are too complicated for average Joe to properly assemble- the tools/pins are terribly documented.  Connectors are under the panel so for many you'd have to unmount every panel to get access for replacing them, very labour intensive.

Can't they do a IR thermal cam scan and look for hot spots, something preemptive ?

I'd love to see more specifics.  I was thinking the "incompatible connectors" they were referring to might be an H4/MC4 connection (works OK, not UL approved), under the panel.  Perhaps the issue is a mismatch of the high-current version of the H4 and the smaller, or using the smaller in a high-current branch?  Those might not be under the panel, certainly not under every panel.  I'm not sure how thrilled I am at the idea of running 65A thru a connector like this, no matter how much additional contact area they've designed in.  I'm really not sure why they are needed.

[floobydust]

Tesla can do leading edge engineering but they are impotent when it comes to manufacturing, and installers are likely inherited from SolarCity, they seem to be from Planet of the Apes if you look at people's post-install videos.

"The faulty parts in question were connectors - Amphenol H4 connectors - and SolarEdge optimizers."
"A portion of SolarCity-installed modules and optimizers from various manufacturers were made with H4 connectors from Amphenol, a part that was commonly used across the industry at the time," a Tesla spokesperson told Business Insider."

Tesla's Project Titan appears to be about fixing some connectors and SolarEdge MPPT power optimizers which can be ordered with one of four different connectors (H4, UTX, MC4, T4). SolarCity could have bungled the connector compatibility, or bad crimps, bad assembly for IP68 etc.

edit: It was the (batch ordered) solar panels were MC4, thus the wrong connectors there. That's data on the quarantined Walmart panels PV-10119-255.

[oPossum]

This article is good, but scroll down for the pictures!  Lots of them!

http://www.acsolarwarehouse.com/news/solar-fires-dc-arc-faults-on-solar-systems/

More pictures here with many showing damaged MC4 type connectors.

https://safersolar.com.au/gallery/

[SparkyFX]

Specialty tools I never see people have them on the jobsite. These are general labourers doing the work.
Amphenol H4 crimping tool H4TC003 is $500, they are expensive so I would expect installers to improvise... unless their employer supplies hand tools.

Rule #1 for every crimp connection: use the proper crimping tool for the contact. Some tools even would produce similar looking results (e.g. square shape), but are made for different ferrules and different forces. Even cheap ferrules and butt wire splice connectors have color coding to avoid selecting the wrong size for the cross sectional area or the wrong crimp tool chamber.

But anyway, once it is possible to interconnect two types that are not supposed to be put in each other, but still kind of work the chaos is perfect.

Automotive crimp connections are not better at this, it is the same kind of problem (no standard, horribly expensive tools), which is why prefabricated harnesses are sometimes mandated/preferred for repairs.

Is there some irony here, Walmart sells MC4 connectors https://www.walmart.com/c/kp/mc4-connectors

LMAO.

Can't they do a IR thermal cam scan and look for hot spots, something preemptive ?

According to the Meet Kevin video, they kind of did it half assed, but for this to identify weak spots you need the proper conditions, the sun must shine and the system better be at peak power output. Otherwise comparison between panels might only identify those that are broken or unconnected. Better than nothing, but it might be too unreliable to do properly.

[bdunham7]

More pictures here with many showing damaged MC4 type connectors.

https://safersolar.com.au/gallery/

As far as I can see, it looks like most of those are not actual MC4, except for some that are 1/2 MC4.  Perhaps there is a connector issue after all? 

[oPossum]

I meant to say there are pictures of connectors that look like MC4. I can't (yet) tell the difference between the real MC4 and something similar. Before this thread started I thought any connector of that style was a MC4 and could just plug in to any mating connector. This thread has been a real eye opener about solar specific connectors, proper installation, and fires.

[floobydust]

150VDC solar array arc example:

220VAC and 1/2 wave rectifier/filter caps:

In many of the (connector related) fire damage pics, it looks like a cascade failure.
A connector with high resistance heats up. It melts, deforms, oxidizes lets water get in. Resistance goes up further and once the housing turns to carbon, that insulation gone, an arc starts and finds a path to anything nearby, usually grounded brackets.

But I also see carbon tracking on a panel's back sheet. The cells must get overloaded during a mid-array ground fault and melt the back sheet?

[bdunham7]

But I also see carbon tracking on a panel's back sheet. The cells must get overloaded during a mid-array ground fault and melt the back sheet?

I'm not sure what happened there, but it is the middle 1/3 of the cells or interconnects that have burned through, or one section out of three that is wired in a unit and bypassed with one diode.  A shorted diode would cause the cells to be shorted, but they should withstand that.  An open would subject the cells to high voltage if they were shaded.  I'd really like to know what happened here as well. 

[bdunham7]

I meant to say there are pictures of connectors that look like MC4. I can't (yet) tell the difference between the real MC4 and something similar. Before this thread started I thought any connector of that style was a MC4 and could just plug in to any mating connector. This thread has been a real eye opener about solar specific connectors, proper installation, and fires.

I've got MC4 panels and MC4 inverters that were produced before H4 and alternatives became popular.  However, if I had gotten one or the other in H4 and the spec sheet said "MC4 compatible" I would have plugged them in without a second thought--but I'd be thinking about it now!  Everyone with a DC system and mixed or unknown connectors ought to be taking a look at this point.

[SparkyFX]

Looks impressive, but lets not forget the arc is just the effect of something breaking that was not supposed to break. If these installations worked flawlessly several years before failure they most likely had been under peak load several times, but something changed/wore out and made it fail catastrophically.

Based on some pictures at https://safersolar.com.au/gallery/ it looks like reduced contact force lead to arcing and fire there. That could have been caused by loss of spring resistance in switches (either in the spring or the plastic  frame it is mounted in), work hardening (does thermal expansion and contraction cause work hardening?) or an oxide layer formed (e.g. through water ingress) and pushed contact surfaces away from each other. In case of DC isolator switches and connectors it might have been caused by enclosures that were not as weatherproof as they should have been, some pictures show how far the green copper oxide creeped.

These might be fixed installations, but vibration from wind and thermal expansion almost call for requirements of mobile applications.

[floobydust]

... lets not forget the arc is just the effect of something breaking that was not supposed to break.

It's not always something breaking, the insulation can degrade as well. I see the connector plastics cooked to carbon and then they conduct to the aluminium bar it is tie-wrapped to, and an arc starts to finish the party.

Amphenol is very heavily into their RADSOK (RADial SOcKet) spring-contact technology, to get 52A ratings on H4.
I wonder if it actually ages well or if manufacturing QC is good enough for the "hyperbolic mesh"? It does not look easy to make/assemble in a pin. No mention of the metals used and I would suspect the connection between the two sleeves does not last.

Another overlooked aspect for DC connections is ion migration at the connection, the connection's metallurgy changes with age, it does oxidize/corrode more than AC. I would guess tin migrates away. That would be seen as a polarity issue for the failures, they might favour a cathode end.

[SparkyFX]

Amphenol is very heavily into their RADSOK (RADial SOcKet) spring-contact technology, to get 52A ratings on H4.
I wonder if it actually ages well or if manufacturing QC is good enough for the "hyperbolic mesh"? It does not look easy to make/assemble in a pin. No mention of the metals used and I would suspect the connection between the two sleeves does not last.

Thanks for pointing their technology out, other material so far did not show these details.

Another overlooked aspect for DC connections is ion migration at the connection, the connection's metallurgy changes with age, it does oxidize/corrode more than AC. I would guess tin migrates away. That would be seen as a polarity issue for the failures, they might favour a cathode end.

I wonder if those are coated, and if so before or after stamping the shape. The specs say it is tinned copper.

I've got MC4 panels and MC4 inverters that were produced before H4 and alternatives became popular.  However, if I had gotten one or the other in H4 and the spec sheet said "MC4 compatible" I would have plugged them in without a second thought--but I'd be thinking about it now!  Everyone with a DC system and mixed or unknown connectors ought to be taking a look at this point.

English Wikipedia states Amphenol H4 as compatible to MC4 (name derived from manufacturer Multi-Contact, now Stäubli, Barrel diameter 4mm; although different diameters available), as well as some list their system as MC4 compatible.

But, there was also a statement of our TÜV Rheinland in 2015 (sorry, german) that strongly advises to only use connectors from the same manufacturer throughout, by lack of standardization and plenty of field defects, found through inspection, reports and subsequent internal long time testing. No certification that allows cross compatibility was actually issued, although stated by companies that had their products tested by TÜV Rheinland. Tests only covered partial aspects, but no conformity was issued.

They state onesided change in dimensions, contact material, outgassing and chemical stability would otherwise not be given or break compatibility overtime.

In other words it is an old hat and yes, i come to the conclusion that government issued inspections are a good thing. 

[floobydust]

Wow, these MC4 connectors have a serious thermal de-rating! Thanks to Stäubli for giving us some data, and saying "don't mix and match" with other connectors.
I'm not sure what typical rooftop temperatures are, but the rated amperage is to 30C and I would cut it in half. Bet people aren't doing that and then add a Y to double input current.
I could find no data from most PV connector manufacturers on deratings.

Amphenol H4 TÜV certificate R 72123201 is no longer valid, there is only one for Amphenol Technology (Shenzhen) TÜV certificate R 50388083. edit: added H4 datasheet thermal derating curves.

Weidmuller has PV-Stick push in (no crimp) the bare wire type of connector, rated 30A. I wonder what magic is inside.

Why can't they just make these connectors a bit bigger and give them true current ratings?

[orion242]

If these installations worked flawlessly several years before failure they most likely had been under peak load several times, but something changed/wore out and made it fail catastrophically.

Water intrusion in the connectors due to improper tightening would explain that quite nicely.  Not a problem at first, yet given time nearly 100% fail rate is almost certian.

Wonder if the teams all had these plastic tools on installs and equipment with mis-matched connectors.  They break the wrenches shortly after they start and walk in wally for channel-locks or resort to hand tightening there on.

[SparkyFX]

I could find no data from other PV connector manufacturers on deratings.

Amphenol has them in their specs too, looks the same. It is not said that other types of connectors (e.g. CEE) do not derate similar, as those temperatures can exceed the maximum 70°C for PVC type insulation or connectors and tests in that direction might therefore be disregarded as improperly rated.

The MC4/H4/.. are however tested according to norms including solar use cases and so on. Solar does have its own set of problems.

Why can't they just make these connectors a bit bigger and give them true current ratings?

Thats exactly how the problem started. The market called for connectors that are safe to be put together by workers not being certified as electricians, and in open environment, whilst there are plenty of other options to connect equipment with similar power (CEE connectors, or simple cable lugs), but those need to be made properly, have a protection against disconnection under power or require permanent installation, which code would forbid to be installed by a layman. Some might work, but need an additional shroud or cover.

Don´t get me wrong, they will do the job and many ideas - that the other options were not built for - went into them, but there seem to be many caveats.

Weidmuller has PV-Stick push in (no crimp) the bare wire type of connector, rated 30A. I wonder what magic is inside.

Maybe a pre-tensioned clamp, similar to WAGO clamps.

[orion242]

PV-Stick push in (no crimp) the bare wire type of connector, rated 30A. I wonder what magic is inside.

They offer free samples so easy enough.

30A 1500v water proof stick on connector has my interest as well.

[thm_w]

Wow, these MC4 connectors have a serious thermal de-rating! Thanks to Stäubli for giving us some data, and saying "don't mix and match" with other connectors.
I'm not sure what typical rooftop temperatures are, but the rated amperage is to 30C and I would cut it in half. Bet people aren't doing that and then add a Y to double input current.
I could find no data from other PV connector manufacturers on deratings.
...
Why can't they just make these connectors a bit bigger and give them true current ratings?

Its not really that crazy de-rating since its based on ambient temperature. But I think you have a good point here, if the connector is exposed directly to sunlight or is in direct contact with the back of the solar panel, it is feasible for it to reach 60C+ which is a ~75% de-rating. So maybe ambient is a bit deceiving to use as a gauge.

[bdunham7]

I think this is all a bit crazy since the implication seems to be that the connector is OK until the contact pieces reach 105C and at lower ambient temps it is just fine to run enough current through them until they heat to 105C.  A little extra resistance and fwoosh! 

I wasn't able to quickly find info on the UL listings for these, but I believe the UL ratings are all much lower.  They recently listed some of the newer connectors for 1kV, but they are 1.5kV elsewhere.  AFAIK, the UL rating for the basic MC4 is 20 amps, period.  And that seems OK.  Running 104 amps through a 4mm connector (if I'm reading this right), no matter how "robust", with an 8ga cable, is just way, way beyond what you get away with in any other area.  There's no way that should be rated for more than 40 amps and I still wouldn't be happy with the connector. 

I didn't know that non-electrician installers were stringing together parallel systems at high current this way.  I wonder if these ratings or listings have been misrepresented to local building code enforcers.  The last I knew--which has been a while--is that the temp help can bolt the panels on and clip the string wiring together, but each string is connected to a combiner box by a real electrician using real wiring and then that electrician does the balance of the wiring, again with real, enclosed-in-conduit wiring.  I guess I'm hopelessly out of touch.  The IBEW should be all over this since you now have seven (eight plus with Amazon) fires possibly caused by crap work.

[sibeen]

I suspect the sheen is wearing off Elon.

https://www.vanityfair.com/news/2019/08/how-elon-musk-gambled-tesla-to-save-solarcity

[floobydust]

From early Amphenol marketing:
"The Amphenol Industrial Helios H4 Solar Connectors are fully intermateable with industry standard (MC4) connectors and are ready for field assembly with no small parts to lose. The RoHS compliant Helios H4 connectors are engineered to meet UL, TUV, IEC/CEI, NEC, and DIN V."

Misleading because they would not be UL approved when cross-mated. Who did the IP68 test and current ratings/derate with H4/MC4 mated? OOPS

Sunday Amphenol gave a statement:
“We have no reason to believe that Amphenol’s products are the cause of any issues related to the claims filed by Walmart against Tesla,” Wallingford, Conn.-based Amphenol said in a statement Sunday. “We stand behind the quality of our products, including the H4 solar connector which was manufactured to meet established industry specifications, and certified to meet those specifications by UL, an independent third-party testing service.”

[orion242]

each string is connected to a combiner box by a real electrician using real wiring and then that electrician does the balance of the wiring, again with real, enclosed-in-conduit wiring.  I guess I'm hopelessly out of touch.

There might be some areas that this isn't the case, but the majority here will require licensed electricians.  Homeowners can get permits to do work on their own homes in some places, but not commercial installs.  Going to need permits, which almost always start with a master electrician.  Last state I was licensed in, >$600 requires permit and anything over class 2 or running conduit requires licensed electricians.  SC certainly could have had a few master electricians that where nothing more than permit handlers and monkeys doing the actual installs.  Wouldn't be much AHJ oversight adding a solar install to an existing building like there would be with new construction.  Pull permit, half arsed install, call for final inspection.  Many times you don't even need a representative present when they inspect.

[orion242]

Would be another interesting look into this.  Permits are likely public or FOIA.  Would be a crap load of work sorting that out over 240+ sites.  Subcontracted out or did SC have a few puppet master electricians that pulled all these?

[floobydust]

each string is connected to a combiner box by a real electrician using real wiring and then that electrician does the balance of the wiring, again with real, enclosed-in-conduit wiring.  I guess I'm hopelessly out of touch.

It's a good point, commercial buildings require all (mains) wiring must be enclosed in conduit. Rooftop air conditioners are wired this way.
I wonder why the NFPA allows loose wires and zip ties for solar systems.

[SparkyFX]

The layout (how many panels are in series or parallel) and therefore required rating per connector is not in the hand of the fitters, there must be plans by someone being responsible -- except they really f´d it by connecting panels in the wrong way and every control failed to notice. But that would be kind of obvious for fire investigators to check how the panels were connected.

60A alone sounds like there might be a lot of safety, a single, state-of-the-art panel generates around 15A@20V max?
Therefore how many panels in parallel to exceed the rating? More than three? The thing with the derating is, the hotter the sun shines, the more you need to derate as the panels generate more current and what works in the northern part of the country might not work in the south.

[orion242]

I wonder what magic is inside.

Heavy spring that appears to snap down on the conductor once inserted and less fiddly tightening procedure from the looks of it.  Your supposed to hear a click when you push it in enough and the bottom edge of that spring is not in the initial conductor path.  Something might break off the "wire guide", that most inner part of the stack up, which looks to be holding the spring up initially.  The spring has a fair bit of force, but would like to see how much contact area there really is with the conductor and the inner pin/spring.  Doesn't look like much on the surface.

8-3-19.jpg is the spring contact inside with the plastic "wire guide" removed.

Looks like the spring is held back by the wire guide and snaps free when the conductor is jammed in.  I pulled apart one of them to get the other picture and don't have suitable cable here to try the unmolested one.  Once the conductor is in, its just hand tighten to seal.  There are knurled bits where the nut meets the main body to try and retain things from slipping loose.  Tightening one down all the way and looking in at the cable seal, its maybe an 1/8" opening so I would think that's a tight seal against a proper conductor.

Have to dig around for a suitable chunk of cable.

These don't have appear to have UL listing, so not something we could use here.

[tautech]

each string is connected to a combiner box by a real electrician using real wiring and then that electrician does the balance of the wiring, again with real, enclosed-in-conduit wiring.  I guess I'm hopelessly out of touch.

It's a good point, commercial buildings require all (mains) wiring must be enclosed in conduit. Rooftop air conditioners are wired this way.
I wonder why the NFPA allows loose wires and zip ties for solar systems.

Here, spec demands solar wiring is to same standard as mains and in conduit.

[orion242]

Been a while since I was up on NEC code here.  When I was...

Class 2 is 50v & 100va and under, no conduit required in most cases.  Above that is class 1 and requires "conduit" of some fashion generally.

That said, each cable type / use / location has numerous exceptions.  For example, romex in residential.  No conduit required where its "protected" in residential.  That's typically in walls, attics that are used not for storage, or protected such it cannot be readily damaged by normal use.  Protected in the open, typically means the cable is in the middle of whatever wood members your passing through.  So a garage without any drywall on the interior, you can use romex as long as its not on the surface of the studs.  Still exposed IMO, but meets code.  You can run 240v 100A romex without any conduit all day long in this case.

SO cord can be used for 480v 3 phase and many times 100va, in certain use cases and locations.  Elevators don't use conduit to make the connections to the passenger car.

Never dealt with solar and far removed from current NEC now, but I would expect there are certain exceptions for solar panels.  I know solar has its own sections in the NEC, never paid any attention to them or was required to.  For starters, have you seen a panel with an enclosed box for the connection and conduit knockouts?  Bit of an issue if NEC requires 100% conduit then.  Can't put a splice in conduit under any condition, so what exactly is the market for these connectors if 100% conduit is required then?

It may be that most inspectors are clueless that some of these are being installed in series/parallel strings at fair voltages and currents.  They are just generally not aware of whats really going on, make assumptions and pass things especially when its a well known name doing the install.  I see a good number of these solar installs and never really paid alot of attention to them.  Until now, I would have never expected to see >300v volts @ ~30A on a innocent little connector like this with free air cable.  Opening that live is going to be exciting I expect.  That stuff just gained a lot more respect/interest next time I'm walking by.

With all the BS OSHA safety crap is around arc flash hazards today, I'm bewildered how a connector like this can be rated for 1KV @ 30A without requiring permanently embossed warnings, high viz colors and LOTO provisions.  1kv AC has an absolute $hitload of safety requirements at any moderate power level.  Internally in a building, your going to have to accommodate that with special construction in most cases.

[David Hess]

With all the BS OSHA safety crap is around arc flash hazards today, I'm bewildered how a connector like this can be rated for 1KV @ 30A without requiring permanently embossed warnings, high viz colors and LOTO provisions.  1kv AC has an absolute $hitload of safety requirements at any moderate power level.  Internally in a building, your going to have to accommodate that with special construction in most cases.

Unlike the AC power line, solar panel outputs are effectively impedance protected by the voltage to current curve of the solar array which limits voltage and current to values not much higher than the typical operating conditions.  So you can get hazardous voltages and currents but power and energy are limited preventing anything like arc flash.

A short just reduces the voltage to zero and raises the current 10s of percent.  The power ends up dissipated in the panels which have plenty of surface area.  If that increase in current causes a connector to fail, then it was defective already.

[SparkyFX]

Opening that live is going to be exciting I expect.

They are built to snap in and "require a tool" to be opened again. No idea if that actually makes them safer, but at least someone thought of that.

I'm bewildered how a connector like this can be rated for 1KV @ 30A without requiring permanently embossed warnings, high viz colors and LOTO provisions

They probably leave that to the person that specs the particular install to place warnings wherever necessary. The connector rating is just it´s maximum,
LOTO probably starts on the DC isolator switch. The thing to remember is... danger is highest when the sun shines, it´s a generator after all.

[tautech]

Been a while since I was up on NEC code here.  When I was...

Class 2 is 50v & 100va and under, no conduit required in most cases.  Above that is class 1 and requires "conduit" of some fashion generally.

Two 300W panels and you're over......actually one, one 300W 9A panel in a 12V installation is 108 VA !

[orion242]

They are built to snap in and "require a tool" to be opened again. No idea if that actually makes them safer, but at least someone thought of that.

Its trivial by hand push the two locking tabs in and separate it.  Tool required on these?  Fail...

LOTO probably starts on the DC isolator switch. The thing to remember is... danger is highest when the sun shines, it´s a generator after all.

I don't typically see isolators per panel.  If they are only installing them at the end of a series string....that's a fair number of connectors with little way to kill the power.

[floobydust]

6" 72-cell commercial panels seem to be around 330-390W, Isc almost 10A or 9.88A full sun, IMPP 9.37A, Voc 48V and VMPP 40V typ.

An arc occuring mid-string would short out the lower (grounded) panels and cause the top panels get +ve overvoltage injected from other parallel strings.
A combiner box has a fuse+disconnect for each string, so there is protection.
Junction box, couplers, splitter has no fuse, there is no fault protection. So a panel can see whatever parallel array current is available which seems to be very high and explains the back sheets burning up, a panel's conductors are sized only for the panel's output current.

I don't think the NFPA/NEC etc has considered this difference between AC mains systems and solar.
A ground fault on a branch conductor can result in higher current than the branch can supply or was designed to.


I realized in a big way, Tesla's solar-shingle electrical connectors are going to have great difficulty not burning up.
It's high heat, water, cold on 100's of connections. Forget about the laminations and the sandwich, it's the connectors that will be his undoing.
Announced in 2016, in 2019 the shingles are supposedly in production but I think vaporware? He has a waiting list, pre-orders etc. and those poor engineers better pull off the miracle soon.

[Marco]

I realized in a big way, Tesla's solar-shingle electrical connectors are going to have great difficulty not burning up.
It's high heat, water, cold on 100's of connections.

I think you could make them contactless. Put down a sheet with an insulated electrical backplane and then glue the shingles to it, with capacitive coupling between them.

Sounds like something which is patented though.

[tautech]

I don't typically see isolators per panel.  If they are only installing them at the end of a series string....that's a fair number of connectors with little way to kill the power.

Once the string has the load removed there is zero current through the connector.
With the current (excuse pun) range of panels sizes and ratings, connectors need only see 10A but granted with a 10 panel string some 300V.

So with 100's of panels on a typical WalMart installation there only needs be some installer wally with the wrong crimper or limp wristed termination into the uInverters and you have a recipe for flame outs, especially with HV DC.

In a tiny 3 panel LV system we're working on has been wired by a registered sparky and every termination has bootlace ferrules.

[maginnovision]

I think they've deployed some solar shingle type roofs. They're not all of the solar type though, only some. Even if a section of the roof is optimal it's only partially the solar shingles. I don't know how many real paying customers have had them installed vrs massive supporters/employees. Even still number of installations seems very low, I can't find concrete numbers though.

[floobydust]

FF past 1:30
Finally found more on the Tesla Solar Roof Tiles- I'm wrong about the connectors, they look like MC4 underneath. The tiles sit up high raised up off the roof, I thought they were flush.
Safety features are having the array floating wrt earth ground, "16V"? diode trunk and loss of AC automatic disconnect.
edit: added pic and I like the hinge but don't like the overlap on each tile for shade and the fact that windy rain will blow water in there.

[orion242]

Nice find.

They sure look nice over standard panels.  What an utter nightmare to find a half dozen dead shingles once you notice something isn't right.

[orion242]

added pic and I like the hinge but don't like the overlap on each tile for shade and the fact that windy rain will blow water in there.

Doesn't look great for a roofing material.

https://ca.brockwhite.com/userfiles/documents/info/2_0800377-firestone-clad-gard-metal-roofing-underlayment_info.pdf

The crap they put below sounds fairly solid, but its certainly not meant to be the final water proofing.  If all those connectors are exposed to water regularly, seems bound to have failures just do the shear number of connections required.  The air gap behind the shingles should allow for quick drying, bonus.  Troubleshooting a failure still looks insanely expensive.  How the hell would you narrow it down?  The "diode trunk harness" and all the wiring is inaccessible without removing the shingles.  Would like to see what this diode harness looks like.  At 14:11 in that video, it might be the vertical thingies at the left side of the video.  Broken up, but those guy pretty much destroyed every part of that install as firefighters seem to do.

[orion242]

With all the BS OSHA safety crap is around arc flash hazards today, I'm bewildered how a connector like this can be rated for 1KV @ 30A without requiring permanently embossed warnings, high viz colors and LOTO provisions.  1kv AC has an absolute $hitload of safety requirements at any moderate power level.  Internally in a building, your going to have to accommodate that with special construction in most cases.

Unlike the AC power line, solar panel outputs are effectively impedance protected by the voltage to current curve of the solar array which limits voltage and current to values not much higher than the typical operating conditions.  So you can get hazardous voltages and currents but power and energy are limited preventing anything like arc flash.

A short just reduces the voltage to zero and raises the current 10s of percent.  The power ends up dissipated in the panels which have plenty of surface area.  If that increase in current causes a connector to fail, then it was defective already.

I understand the flash part is certainly not an issue as it is with mains.  The available fault currents are very different.  The arc potential though if they are running high voltage DC setups certainly is there.

High viz vest, safety glasses, hard hat, work boots just to be in a 99% complete building, yet this kind of arc might be possible opening a non-descript connector?  Working on anything live, holy crap...its a PPE nightmare these days.  Flame retardant undies, everything must have labeled fault currents, etc.  Nearly impossible to comply and still operate.  I look like an astronaut to check low voltage controls on high power circuits and barley have any fine movement control at that point, which IMO is more dangerous than all the BS one has to wear..  There are certainly cases the village idiot is on a roof near these installs and may decide to move them out of the way for a minute.  How about the Tesla moron walking on the panels decides to inspect the connectors.  As a former non-solar sparkie, I would have never expected that kind of power on something so simple to access and disconnect by hand with free air cabling.  Will it blow up in your face like mains, doubtful.  Could it burn the hell out of your hands and pose a serious shock hazard, looks possible.

Personally, I don't think the NEC/AHJ is aware of the potential issues with these installs.  Admittedly, I don't know enough what common practice is on these installs either.   Anything close to 1kv @ 30a Dc on these connectors is insanity without full LOTO.

[floobydust]

Heat with full sun at 800-1000W/m^2 while generating electricity into a short-circuit- that is extra heat for the cells.
I think the connectors and module internal interconnects can see much more than ISC if there is an arc, as other panels in the system contribute, they are generating current in parallel connection and we're all too cheap to use a fuse or extra diode barrier there.

Walmart and Tesla are now "actively negotiating to resolve the lawsuit" to contain the hull breach. The fact that Walmart has sue Tesla to get them to act and fix the substandard installations, is really terrible.  Ma and Pa would be totally ignored if they had any troubles with their solar system, including the fire.
I can't tell if the company is selling unicorns and rainbows but the conflicts of interest around the purchase of SolarCity really says something creepy about the business priorities.

Heat a mated connector and wires to say 70C and dunk in cold water and see what happens. Similar to a hot connector suddenly get cold rain from a thunderstorm- water gets sucked inside. I've seen many products fail because the seals malfunctioned during the cold shock, or the tiny pressure change internally makes a low pressure, or the housing did not contract fast enough to keep seal tolerances.
So I am not a fan of outdoor connectors being immersed or getting wet at all. The Weidmuller PV stick is only IP65, but Stäubli MC4, Amphenol H4 are IP68.

[SilverSolder]

We are still in the early days of the solar industry...  -  What's the betting that in time,  regulations will require solar panel wiring to be completely enclosed...   -  which, after reading this thread, is what I would be insisting on with any installation I have anything to do with!

[Marco]

Instead of corded connectors, why don't solar panels simply have sockets on the junction box? It would vastly reduce the exposure of connectors to water.

[floobydust]

Amphenol UTX was subject to recalls in late 2016, vendor contaminated plastic which cracked and allowed moisture ingress and shock hazard. Tesla is right to implicate them.

The industry has too many different proprietary connectors that come with the panels. They all just might plug into each other... and there's no safety agency approvals or tests on how they do when cross-mated. It's a mess.

There are some junction boxes with MC4 on there, I think it's convenience to have the connector on flying leads.
The panel junction boxes seem to run hotter than everything else?
Here are thermal pics taken from photovoltaikbuero which show a shorted bypass diode, and an open string within a three string panel.

The open string runs hotter- which is counter-intuitive:
"In order to understand the image, keep in mind that solar cells in an open-circuit state are about 2-3K warmer than cells operating based on maximum power point (MPP). This is because, in an open circuit, all of the solar energy that’s not reflected from the panel is turned into heat in the panel; in the case of MPP, on the other hand, some of the energy is drawn from the panel in the form of electricity. As paradoxical as it may seem, this current leads to cooling. Unlike in the case of a short-circuited bypass diode, for this fault you won’t see the typical image with some much warmer cells, like in the thermogram above. Here, all cells in the affected area are equally warm, and the panel socket looks much warmer than its surroundings."

[orion242]

Amphenol UTX was subject to recalls in late 2016, vendor contaminated plastic which cracked and allowed moisture ingress and shock hazard. Tesla is right to implicate them.

"Sold At:
Solar panel installers nationwide from November 2016 through December 2016 for about $330 per solar panel with the connectors."

Ok Tesla can blame how many installs on a specific connector only available for two months?  They were installing these over a several year period, most before Nov '16 off memory.  Site after site with issues, doesn't sound like this is going far to explain things.

we're all too cheap to use a fuse or extra diode barrier there.

Maybe there is a recall on the bolts used in the fuse holder as well.  lol.

Ma and Pa would be totally ignored if they had any troubles with their solar system, including the fire.

Agree, it sure sounds like the wild west yet on these installs, codes, etc.  Resi setup whatever.  Smaller number of panels, the crews are likely a bit better and actually give a rip.  Almost always local and don't want to piss in their pond.  Hundreds of panels installed across the country as cheap and quick as possible, bit more scary.  Step above traveling carnies I suspect.  Install and never seen again.  Only part they brag about is how quick they did it.

Have a new customer now with a commercial scale solar install.  Haven't had a reason to be on the roof yet.  Next visit there, I'm checking it out.

[orion242]

I've seen many products fail because the seals malfunctioned during the cold shock, or the tiny pressure change internally makes a low pressure, or the housing did not contract fast enough to keep seal tolerances.

Water is nearly impossible to keep out 100% if exposed outdoors.  Seal it perfectly in an outdoor enclosure, hard problem.  Condensation is a big problem.  Hot and humid when you perfectly seal, ambient temps fall at any point you have condensation to deal with on top of the pressure change.   If any air can enter, condensation is a compounding issue.  Underground conduits can collect water in the driest places if air can get in.  Its almost guaranteed to have water to some degree with wide temp swings and exposed to weather.

The longest lasting connections in outdoor enclosures I have seen, have tight sealing covers/openings but make provisions for water to escape.  Aka, specifically designed to be open to atmosphere and using gravity to remove the little water that does get in.  Seen numerous enclosures with robust sealing that just trap in water and fill up if they didn't allow for water to escape.  Open the cover and it pours out, connections submerged in water and completely nackered.

Underwater, aka water proof doesn't need to deal with the wide temp swings as something outdoor.  The pressure/condensation problems are minor compared to sitting on a roof.

[floobydust]

The point is Amphenol had a plastics quality problem that caused the connectors to fail, albeit in late 2016 but recalled due to an installation company encountering the problem.
Would Amphenol be forthright over dangerous quality issues otherwise, or just sweep it under the rug? Let's replay their official PR response, oh wait it been scrubbed from the Internet as their stock takes a big hit over this. Just amazing.
You need connectors with batch/serial numbers it seems. How does Ma and Pa know if their connectors are affected?

Weather-Pack/GM/Delphi/Aptiv and Deutsch automotive connectors use triple-lip silicone rubber seals for both the housing and wires. Under the hood, you get extreme temperature excursions and water splash- they are proven to work very good. They have no agency approvals or HV design of course.
Why are PV connectors sealed with only one tiny o-ring? Expected to last 20 years? They could be built much better and not as cheap.


I think a drone fly-over with thermal imaging cam would be well worth it to spot problems on the panels, but the wiring is underneath so we need a small rover with thermal cam to drive underneath. Musk should postpone his Mars work, and maybe make an inspection robot.

[G7PSK]

This is a humorous look at this.

https://youtu.be/f58ohDLw6Tw

[Marco]

There are some junction boxes with MC4 on there, I think it's convenience to have the connector on flying leads.

You could also have the default be one socket and one flying lead on the junction box, for simply attaching neighbouring panels you would still have everything at hand with the panels.

For every string there would be only one connection which the (amateur) installer would be tempted to simply leave dangling on the roof surface, instead of one every panel.

[floobydust]

We want the convenience of plug-in connectors, so a plumber can wire a rooftop installation within minutes.

Any electrical connector located outdoors has a really hard life. It's getting attacked by UV, heat, water, ice, oxidization, vibration from wind etc. I guess all we can do is protect them from as much as possible.

A lot of mechanical engineering seems to have gone into the panel's mounting struts and extrusions, with no thought about the wiring, just use low cost tie-wraps that age and easily break. A simple cable-tray might be better and could be part of the extrusions as a U-channel, to keep the connectors and wiring from laying on the roof.

The industry is kind of screwed, with over a dozen different panel connectors that are implicitly "MC4" compatible. The connectors need to be open-source - which could never happen due to certification costs or quality control.
Stäubli (Multi-Contact) surely has the tight tolerances and quality German manufacturers are renowned for. But nobody wants to pay extra for that, so Cheap Panel Co. makes their own connectors which come already assembled to their panels.

[SparkyFX]

The point is Amphenol had a plastics quality problem that caused the connectors to fail, albeit in late 2016 but recalled due to an installation company encountering the problem.
Would Amphenol be forthright over dangerous quality issues otherwise, or just sweep it under the rug? Let's replay their official PR response, oh wait it been scrubbed from the Internet as their stock takes a big hit over this. Just amazing.
You need connectors with batch/serial numbers it seems. How does Ma and Pa know if their connectors are affected?

Incompatible to "Freedoming", but we´re getting political here.

Weather-Pack/GM/Delphi/Aptiv and Deutsch automotive connectors use triple-lip silicone rubber seals for both the housing and wires. Under the hood, you get extreme temperature excursions and water splash- they are proven to work very good. They have no agency approvals or HV design of course.

There are known cases in which engine oil was pulled through an oil pressure sensor wiring into the engine controller - which does have a pressure equalization valve(?! No idea how it would even be possible). Utilizing the insulation as a hose. So yeah, it is kind of airtight.

But when it comes to high power, it is all crimped or crimped cable lugs on zinc coated bolts.

Why are PV connectors sealed with only one tiny o-ring? Expected to last 20 years? They could be built much better and not as cheap.

Cost-optimized to death... seriously, if it was up to me i´d go with a hardwired install, crimped cable lugs mounted to a busbar, in metal enclosure with added pressure equalization membrane, ideally under a shroud. But yes, it is probably more expensive to install.

I think a drone fly-over with thermal imaging cam would be well worth it to spot problems on the panels, but the wiring is underneath so we need a small rover with thermal cam to drive underneath. Musk should postpone his Mars work, and maybe make an inspection robot.

Speaking of reinventing the wheel:

[Marco]

Another stupid question, why don't solar panels come standard with a peel off cover? Given how frequent high voltage strings are used it would seem a convenient protection.

[SparkyFX]

At first they are usually isolated high voltage DC, which means safe to the touch unless there is a ground fault.

As far as i understood there is a glass-like front over them already, mostly for mechanical and chemical reasons, as they need to withstand hail and ice to some degree and that also serves as electrical insulation. Another cover would block/filter a certain amount of sunlight and any peel off film does usually not withstand the weather for a long time.

[Marco]

It needs to last a couple of days at most, blocking sunlight was kind of the point ... a vinyl peel off film will last a lot longer than that.

[SparkyFX]

Ohh! You mean during installation or maintenance to block them from generating voltage? I guess so you can inspect them for damage before you haul it on the roof. Installers might have cloth and clamps for that case.

Electrically the safety depends on the order in which things are connected, I don´t see a problem if the isolator switch is toggled last. The connectors probably burn/spark only while conducting high currents, so as long as the circuit is open at the isolator switch, there is no tendency for arcing.

[tautech]

Another stupid question, why don't solar panels come standard with a peel off cover?

Considering all the plastic waste that would arise those with a real green bent that install PV's might be offended by such a consideration. 

Given how frequent high voltage strings are used it would seem a convenient protection.

We did a 3 panel 300W jobbie the other day and just left one connector open until everything else was finished.
Easy with a tilted array but not so if they are mounted flat.

[Marco]

Considering all the plastic waste that would arise those with a real green bent that install PV's might be offended by such a consideration. 

At a couple 10s of microns it's really not all that relevant, doesn't make a mess either unlike the foam packing.

[SparkyFX]

It depends on what the users/handlers think about such solutions and if the amount of linked accidents during installation is really so high that it justifies demanding this for every panel produced. If it electrostatically charges the panel while peeling, it might damage other parts of the installation and the manufacturer would have a hard time to work out the claims, so it can´t be cheap plastics, it needs to be defined conductivity or special properties, non stick/weld/adhesive type that is guaranteed to not stain the surface, would need additional chemical cleaning or attract dirt electrostatically. The devil is in the details for this special sauce.

I guess if one installs dozens of these, it might be more annoying than it helps with safety, as this means you need to collect large volumes of trash on the roof and need to get it down safely. Plus the unnecessary waste disposal takes time and if these go flying you annoy the neighbors too, forget to remove them and you need additional service. If it prolongs the process, requires more tools or creates new safety risks, raises additional costs it might not be worth doing.

I personally think as this would be a one time use only thing, it´s probably not considered eco friendly. Of course it is a ridiculous low amount per panel... but even apart from that, i think it would be a waste of resources and money. With guaranteed recycling some energy of it might be preserved, but thats not mandatory everywhere. In the end you´d pay triple: higher purchase price, additional process time on the roof, disposal cost just to avoid doing things in the right sequence.

[orion242]

Another stupid question, why don't solar panels come standard with a peel off cover? Given how frequent high voltage strings are used it would seem a convenient protection.

What does this really accomplish, protecting the installing crew from HV?  With the inverter disconnected, everything dry, shouldn't be a huge hazard. They could just leave the panels in a string disconnected till that string is ready and stab these connectors together under no load.  Walk down the string and stab together in 5min or piss around pulling this off every panel and disposing.  Labor cost vs safety improvement, non-starter I assume.

How the hell you shut it off later in life without disconnects per panel, seems a bit more fiddly.  Its high noon, your crap is arching / on fire single or few panels and need to stop everything in that string...now what?

I can't wait to check out a commercial install.  Want to see how they deal with these strings, the connectors, wiring, disconnects / combiners, etc, etc.  Do they put the connectors up high under the panels with drip loops or lay them on roof?  Where is the fusing and disconnects? What are the ratings on the fusing / disconnects.  Ground fault protection?  Grounding of the install in general?  And on and on and on.  Not grounded, fine...but if the village idiot can open 1kv 30A connector by hand, your body could be completing that circuit when the arc starts grounded or not.  That mistake likely only happens once.

I might break down and ask for tour and take a vaca day if I don't end up back there soon.  Will be snapping plenty of photos and unless its a total horror show, will share.

[tautech]

I can't wait to check out a commercial install.  Want to see how they deal with these strings, the connectors, wiring, disconnects / combiners, etc, etc.  Do they put the connectors up high under the panels with drip loops or lay them on roof?  Where is the fusing and disconnects? What are the ratings on the fusing / disconnects.  Ground fault protection?  Grounding of the install in general?  And on and on and on.

I might break down and ask for tour and take a vaca day if I don't end up back there soon.

I think for the competent handyman a PV installation is not too difficult or challenging especially if the PV string voltage is not too high.
A small array I've done recently using just three 300W panels we looked at different panel orientations to enhance weather tightness but the panel lead boxes though rated IP68 looked like they'd be best at the top of the panel so their leads exit lower down....common sense.
Explicitly their interconnects are labeled as NOT to disconnect or connect under load and each panel had several points marked as suitable for earths or strapping points.
As for the interconnects on these panels I think they were some copy of ones described earlier in this thread however common sense would have one cable tying them out of the weather and out of harms way like puddles should they be installed flat.
One thing I have picked up from this thread is the heat issue under the panels that might impact on connector reliability so we strapped them onto the inside of the alloy frame where they might be better.
Drip loops should always be considered and where we could we incorporated them....again, common sense.

I too would like to inspect a commercial installation so when next at our sons place in Perth I'll have a look at his new 21 panel installation with the view to learning something....or not ! 

[orion242]

A lot of mechanical engineering seems to have gone into the panel's mounting struts and extrusions, with no thought about the wiring, just use low cost tie-wraps that age and easily break. A simple cable-tray might be better and could be part of the extrusions as a U-channel, to keep the connectors and wiring from laying on the roof.

I suspect this is a big part of the problem when you expect to use low skilled labor to slap them in.  The panel racking should have provisions for this that make it harder to do a piss poor job.  Sure you cannot prevent total hacks, but you can make things easy enough it only the bottom feeders that do otherwise.

You have the panels themselves which are waterproof and block UV.  Ice, UV and a lot of BS should be easily avoided if these connectors have a convenient spot behind the center of the panel to attach them such that they are the highest point the in cabling.  The rest of the racking should have wire chases in mind for interconnection between panels and whatever combiner / disconnect requirements there are.

[orion242]

I think for the competent handyman a PV installation is not too difficult or challenging especially if the PV string voltage is not too high.

Ditto.  My shed is solar and at that and even modest home, the power levels are a nothing burger.  I'm thinking commercial installs,  well in excess of 100 panels.  Wallyworld isn't putting a few kwh of panels on their roof.

Explicitly their interconnects are labeled as NOT to disconnect or connect under load and each panel had several points marked as suitable for earths or strapping points.

For starters, its almost designed to be easily disconnected by hand.  An idiot would likely just find it natural to pull them apart by hand.  That alone is a design fail for something rated at this power level IMO.

Second, if you do not have a way for someone above the village idiot to use properly rated disconnects to make this safe in all conditions, another fail.

If the general install practice is to leave these connectors on the roof or in low points...not really a connector specific issue but another likely fail.

[tautech]

Explicitly their interconnects are labeled as NOT to disconnect or connect under load and each panel had several points marked as suitable for earths or strapping points.

For starters, its almost designed to be easily disconnected by hand.  An idiot would likely just find it natural to pull them apart by hand.  That alone is a design fail for something rated at this power level IMO.

Not so much as you might think.
The interconnects on the panels we used clip together and won't just pull apart so when inspecting them closely to find how they might disconnect the warnings are plainly visible.

[orion242]

The panels I have and the connectors under this thread I ordered sample of....

Village idiot would naturally walk up and disconnect by hand.  It seems ergonomically designed for simple hand disconnect.

For that matter, inspecting these connectors if being used at anything near their ratings seems questionable.  Let the village idiot pull them from a pool of water and inspect?

[tautech]

The panels I have and the connectors under this thread I ordered sample of....

Village idiot would naturally walk up and disconnect by hand.  It seems ergonomically designed for simple hand disconnect.

Ones here are different and you need a tool or say long nose pliers to squeeze the retaining clips in to allow separation.

[orion242]

We will have to differ on that point.  Maybe your area uses something completely different.

I have a sample of the connectors and will post a video on how hard it is.  These things look no different than the "MC4" crap I have on my own panels.  Tool required my arse.  Its a perfect setup.  One hand to depress the tabs with another hand to pull the opposite end out.  Insert body to circuit here...

[orion242]

Correction, I have a sample of the push on wire connectors for solar.  These are not UL listed so doubt they are even legal to use here.  Its the same format still.

I have little doubt they will mate with my panels just as easy to hand disconnect.  Will check and report back.

[orion242]

Made it up to the roof of a local solar install.  Been drizzle for the last two days, so everything is soaking wet.  Didn't spend a lot of time and sure wasn't going to be poking around in that weather.

Looks like a pretty clean install.  I couldn't find any major faults.  The panels are just above the roof, bolted to metal racking.  There is a slight tilt to them, but 3-5" off the roofing material.  All the wiring is under the panels, didn't spot any of it laying on the roof.  Where its connecting between rows, the wiring is in a split loom and neatly tied to the racking.



Where there is an interconnection between panels of any distance, its in EMT conduit.  Looked like the ends of all these runs have a bonding bushing with a 12AWG wire tied to the racking.




There must be a fair number of panels grouped together with a single disconnect.  Didn't count them all, but there was probably half dozen of these disconnects connecting these groups to the main wiring feeding to the inverters.  This main wiring is in a metal trough winding through the install.  Sun doesn't look to be doing that plastic disconnect handle much good.  Install is ~6yr old.



Only real damage I could see was some of the covers on the wiring trough was bent up.  Not sure how that happened.  Hard to imagine water getting trapped in and freezing causing that.



The number of disconnects seems pretty sparse for this many panels.  Guessing if a group of panels decide to go up, your letting the fire department deal with it.  Access isn't that great with all the panels, wiring and gas lines running all over.

If its dry next time I'm out there will have to see if I can see how things are ran under the panels.  Suspect its pretty neat and tidy.

[nctnico]

Only real damage I could see was some of the covers on the wiring trough was bent up.  Not sure how that happened.  Hard to imagine water getting trapped in and freezing causing that.

Probably thermal cycling. I've seen that before on similar cable ducts which run in a long section without room for shrinking/extending.

[orion242]

Almost has to be.  Strange thing is that's the shortest run of the main feeds.  You can see a 90deg turn in the photo.  Just off the opposite end of the photo is where it transferred in to what look like at 3x conduits 2" or greater into the building.  The trough was not physically connected to the conduit.  There are runs 3-4x that length without any damage.

Whatever, its minor.  This install isn't anything that wally world describes.

What voltages and power levels its running at, TBD.  What I call disconnects seem to also be the combiners.  Going to try and find the installers as-builts if they exist.  Will be digging deeper to see if I can see how the panels are connected and how everything is connected.  The install looks pretty clean.   Servicing panels looks like a nightmare.  Not sure the owner has any documentation on how to make anything safe.  There are only a few narrow paths to the back of the roof full of trip hazards, least unless your solar city and walk on the panels.

Only complaint, WFT does anyone do to eliminate or seriously reduce the hazard in the event of an emergency?  Its hopeless to have any idea what your disconnecting up there.  Bit of searching on those disconnects didn't produce warm and fuzzies.  That company seems to have removed all pages related to that arm of their company.

[floobydust]

It looks nice but then I cringed. Are these loose wires?
I would let the camera look underneath the panels, where the drama is. How the wiring gets into the conduit is likely to be... interesting because these installations are a mix of commercial building electrical code, and low voltage DC practices.

[orion242]

It looks nice but then I cringed. Are these loose wires?
I would let the camera look underneath the panels, where the drama is. How the wiring gets into the conduit is likely to be... interesting because these installations are a mix of commercial building electrical code, and low voltage DC practices.

As I said everything was soaking wet.  At my age, I'm not touching anything that could put me at a disadvantage.  Dripping and standing in water = avoiding hazardous voltages even practicing safety 3rd.  Could not see much under panels unless I wanted to lay on the wet roof.  What I did see, looked well installed.  Will be back when the weather is more reasonable to get pictures under the panels, inside the disconnects along with some voltage measurements of the feed in and main wiring.  Just not going that deep soaking wet   Disconnects seem to be rated 1kv 400A.  Things get pretty exciting at that level and they just feed the main wiring.

[floobydust]

I would not go near that disconnect enclosure as it very likely has water getting in because the one conduit hub/fitting is a bodge, and the handle may not be sealing after all that UV and heat. This means HV boots and gloves, and if you do open it, let it air out and dry before poking around. Condensation can also get inside.

A big problem with rigid conduit is the popular fittings don't seal and are not waterproof. Proper weatherproof fittings cost a lot more money and most electricians forget a gasket or bodge together something that doesn't really seal over the long term.
Second big problem with rigid conduit is Code considers it a ground conductor, so no dedicated ground wire is needed. I wonder how that was dealt with in the fiberglass enclosure... ground bushings are needed there. Maybe it was done right but I trust nothing until I've seen how it was done.

[SilverSolder]

[...]  Maybe it was done right but I trust nothing until I've seen how it was done.

Distrust, but verify!

[orion242]

I would not go near that disconnect enclosure as it very likely has water getting in because the one conduit hub/fitting is a bodge, and the handle may not be sealing after all that UV and heat.

That conduit fitting meets code.  Granted I share you opinion its not water proof, but there is nothing I see that wouldn't pass inspection.   PCV conduit solvent welded in the dessert will have water in it.  That enclosure should have holes in the back to drain water.  Its inches off the roof so that's still something to think about.  If it is collecting water to a point its in contact with anything live, its going to die in short order.  That could be the moment the cover is opened.

Checking they bonded the ground thru that plastic enclosure is a quick test, really not the main issue I would have opening it.  The contact hazard is nill unless you want to hold the conduit while poking around inside.

Opening the disconnect and it fails..arching over in your face.

Bypassing the door latch and the metal connection between the plastic handle & disconnect falling in the wrong spot.

Biggest hazards IMO.

Normally an AC guy and these issues are present when working with high fault current devices.  Shock hazard minor vs things blowing up in your face if your not aware of what can go wrong.  These days you need a space suit to do this kind of work OSHA compliant.  IMO that's only trying to prevent fools from hurting themselves while making it nearly impossible to preform the work required.

[SilverSolder]

[...] These days you need a space suit to do this kind of work OSHA compliant.  IMO that's only trying to prevent fools from hurting themselves while making it nearly impossible to preform the work required.

The rules are there for a reason!

[Brumby]

^^^   Luke Skywalker I   ^^^

[orion242]

The rules are there for a reason!

Agree.  Its to prevent any problems 100% without any consideration on the impact of actually preforming the work or the IQ/training of the people performing said work.  Loss of dexterity causing more cases that require that level of protection, not part of equation.  Its got to be safe enough for anyone capable of holding a screwdriver.

Let just look at this install.  Where is the fault current rating listed on this disconnect?  Can't touch it without a full system evaluation by PE if its not listed unless it can be powered down.  Open the disconnect...everything is still powered in most all cases.  In this case, the handle could likely break off due to UV before the disconnect opens.  Even opening the disconnect doesn't improve the safety factor with in this enclosure.  This is part of where I think the code hasn't caught up with reality.

Have the space suit in the car.  Expires more often than I use it typically.  I rarely see other sparkies wearing it either unless they suspect the equipment is total junk or the site is willing to swallow the costs without question.  The number of sites with arc flash ratings listed everywhere is almost nill.  Even new construction this is rare from what I see.

Would watch modern hi-rise, hasn't changed all that much IMO.  Sure the steel guys wear a harness for effect.  Note the 100% tie off use and 15-20' below platform/netting they are supposed to land on if they do fall.  From what I see, the fines have become a cost of doing business coupled with the fact they seem to know prior when OSHA is coming.