Author Topic: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!  (Read 4010 times)

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Offline orion242

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #125 on: September 14, 2019, 03:06:49 am »
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.
« Last Edit: September 14, 2019, 03:38:52 am by orion242 »
 

Offline tautech

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #126 on: September 14, 2019, 03:47:14 am »
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 !  :)
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Offline orion242

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #127 on: September 14, 2019, 03:48:01 am »
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.
 

Offline orion242

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #128 on: September 14, 2019, 03:55:25 am »
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.
« Last Edit: September 14, 2019, 04:09:13 am by orion242 »
 

Offline tautech

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #129 on: September 14, 2019, 04:02:53 am »
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.
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Offline orion242

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #130 on: September 14, 2019, 04:11:43 am »
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?
« Last Edit: September 14, 2019, 04:23:05 am by orion242 »
 

Offline tautech

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #131 on: September 14, 2019, 04:19:40 am »
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.
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Offline orion242

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #132 on: September 14, 2019, 04:25:53 am »
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...
« Last Edit: September 14, 2019, 04:38:29 am by orion242 »
 

Offline orion242

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Re: eevBLAB #64 - Tesla Solar Panels Are CATCHING ON FIRE!
« Reply #133 on: September 14, 2019, 04:35:51 am »
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.
« Last Edit: September 14, 2019, 04:39:55 am by orion242 »
 


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