Wall-plug Solar?

[Kontakr]

Has anyone used wall-plug solar units in an apartment? I understand (or at least I believe I do) the risks of backfeeding a circuit and the hazard of exceeding safe loads on the wiring, but it looks to be about the only viable way to add solar to a building I can't change.

[NiHaoMike]

You can use feedthroughs (copper foil sandwiched between insulation plastic) to run the wires inside without drilling any holes. Simply insert halfway in a door/window (preferably one that is not frequently used) and carefully close it so the feedthrough fits into the gap.

[Seekonk]

Are you talking about those cheap grid tie units that plugs into a wall outlet?

[David Hess]

In theory it can be safe to do.  Grid tie inverters are suppose to shut down if AC power is lost and should be protected against various faults like excessive current but the quality and reliability of cheap plug-in grid tie inverters is questionable.

[fourtytwo42]

I assume we are talking the cheap chinese things on Ebay typically 300, 600 or 1000W intended for just a few panels.
My biggest concern with these indoors would be fire, I have seen pictures of these units failing badly. Next biggest concern is electrical hazard, that is no or defective anti-islanding protection (meaning the output continues to provide grid voltage into an otherwise dead grid). There have been various reports of them being unreliable but also some people very pleased with them so it seems to be a bit pot luck! Try exhaustivly to find reveiws for the one you are considering before you buy, that doesnt always work as often designs change frequently. Consider finding somewhere fire resistant or never leave it operating or plugged in unattended. One other issue is approval by your electrical company, it may be worth checking what requirements they have for the use of GTI's and also the compatability or otherwise of your electricity meter.

[Kontakr]

Are you talking about those cheap grid tie units that plugs into a wall outlet?

Those are the ones I'm talking about. I've really only seen cheap ebay models that plug in, and one or two of those websites that look like they were made in the early 2000's way overselling what the panels can do. I was wondering if there was a more reputable manufacturer that I could trust to not kill me in my sleep, but also not skyrocket costs.

My biggest worry is fire or damage to the apartment, plus the general hassle of moving them. I'm not too worried about the electric company aspect, as I would not have enough power to overcome the idle draw of my house.

[f4eru]

Has anyone used wall-plug solar units in an apartment?

That's illegal and dangerous.
Do you want people to die just for a few euros of solar power

Don't. Do. That.

[fourtytwo42]

Has anyone used wall-plug solar units in an apartment?

That's illegal and dangerous.
Do you want people to die just for a few euros of solar power

Don't. Do. That.

Thats a bit over the top! The legality is entirely dependant on the regulations in your country for a start and they are not nececerally dangerious as some have been tested and comply with anti-islanding rules. Sweeping statements don't help anybody.

[f4eru]

Yeah, Could be that they are approved in a few countries
But it's still illegal in most other countries.
And it's still really bad practice to put a generator onto an uninsulated male plug.
Even if the software prevents it from  running when disconnected.

[fourtytwo42]

But it's still illegal in most other countries.

Really, well its not illegal in my country, name some of these "most other countries" where you think it is and while you are at it perhaps you could enlighten us with your location ?

[Gyro]

Sorry?? 

You really think it's legal to put mains on a 13A plug?

[David Hess]

You really think it's legal to put mains on a 13A plug?

If the grid tie inverter is working correctly, then there is no mains on it until it is plugged in.

Existing grid tie inverters use fixed wiring, correct?  What do you think caused the situation where a temporary grid tie inverter installation would even be desired?

[Gyro]

As you say, existing grid tied inverters are properly installed with fixed wiring at  the incoming supply meter with appropriate isolators etc.

I really wouldn't trust a cheap ebay job, which I'm sure doesn't carry appropriate approvals, with it's output on a bare mains plug and assume that it might do the right thing in all circumstances.

But it's still illegal in most other countries.

Really, well its not illegal in my country, name some of these "most other countries" where you think it is and while you are at it perhaps you could enlighten us with your location ?

I'm sure there are very strict regulations over the proper installation of a grid tied inverter.


EDIT: In the UK, grid tied inverters (up to 3.68kW) are governed by the Energy Networks Association G83 standard. This permits a properly specified inverter to continue to output for up to 5 seconds after loss of mains supply. Absolutely not safe on a mains plug!

http://www.energynetworks.org/electricity/engineering/distributed-generation/distributed-generation.html

EDIT1: Also prohibited by BS7671 IET Wiring Regs (551.7.2 (ii)). It apparently prohibits parallel connection of a 'generating set' in parallel with the mains by means of a plug and socket.

https://www.scribd.com/presentation/259597021/17th-edition-overview-ppt

[David Hess]

EDIT: In the UK, grid tied inverters (up to 3.68kW) are governed by the Energy Networks Association G83 standard. This permits a properly specified inverter to continue to output for up to 5 seconds after loss of mains supply. Absolutely not safe on a mains plug!

I wonder if that standard is based on an older technology like phase locked AC generators.  The application notes I have seen for grid tie inverter design use a current driven high impedance output so if the AC power is removed, the output shuts down immediately because a fault is immediately detected.

I really wouldn't trust a cheap ebay job, which I'm sure doesn't carry appropriate approvals, with it's output on a bare mains plug and assume that it might do the right thing in all circumstances.

This is what I would worry about and I have read stories about these things burning up due to inadequate self protection or derating when too much solar power was available.

[Gyro]

David, I just edited my post above. It's also prohibited by IET Wiring Regs. That's a showstopper.

I wonder if that standard is based on an older technology like phase locked AC generators.  The application notes I have seen for grid tie inverter design use a current driven high impedance output so if the AC power is removed, the output shuts down immediately because a fault is immediately detected.

It could well be. The trouble is that it's still in there, so is permitted.

[NiHaoMike]

I had the idea to develop a grid tie inverter where a mains frequency transformer in a separate enclosure was used to interface with the grid. (That transformer could be a common AC wall wart for an experimental/educational setup.) The inverter circuit itself is then low voltage and far safer to work on. As a low voltage circuit, it would also not be subject to the UL requirements that apply to mains connected circuits.

It turns out, though, that for a small solar setup, it makes a lot more sense to not use an inverter at all. Still, I would like to see an open source grid tie inverter as an alternative to the cheap, unreliable Ebay units.

[fourtytwo42]

As you say, existing grid tied inverters are properly installed with fixed wiring at  the incoming supply meter with appropriate isolators etc.

I really wouldn't trust a cheap ebay job, which I'm sure doesn't carry appropriate approvals, with it's output on a bare mains plug and assume that it might do the right thing in all circumstances.

But it's still illegal in most other countries.

Really, well its not illegal in my country, name some of these "most other countries" where you think it is and while you are at it perhaps you could enlighten us with your location ?

I'm sure there are very strict regulations over the proper installation of a grid tied inverter.


EDIT: In the UK, grid tied inverters (up to 3.68kW) are governed by the Energy Networks Association G83 standard. This permits a properly specified inverter to continue to output for up to 5 seconds after loss of mains supply. Absolutely not safe on a mains plug!

http://www.energynetworks.org/electricity/engineering/distributed-generation/distributed-generation.html

EDIT1: Also prohibited by BS7671 IET Wiring Regs (551.7.2 (ii)). It apparently prohibits parallel connection of a 'generating set' in parallel with the mains by means of a plug and socket.

https://www.scribd.com/presentation/259597021/17th-edition-overview-ppt

Ahh thank you for finding it in the wiring regs I must confess I missed that however just to be clear this does not make it illegal, it is not a criminal offence to disobay the wiring regs BUT you would be held liable for any damage caused by not conforming to them.

I agree in general with what everybody has said BUT these units may be used with care and awarness of the potential consiquences, to declare them illegal is simply misleading.  Most unit's I have seen advertised are carefull to state they are CE certified and G83 complient and I have read several articles by people who have sucsesfully used them.

A lot of equipment available to people is potentially dangerious if missused or someone with insuficient knowlage tampers with it but I personally do not think everybody else should be penalised as a result.

I quote from wiki and this is also the situation understood by many people "Electrical work does not have to be compliant with BS 7671, but if a casualty or fatality occurs as a direct result of that electrical work, and this results in a legal action, then it may be necessary to justify major deviations from the principles of BS 7671 and other appropriate standards."

[Gyro]

"held liable" and "legal action" are a good enough pointer for me. 

[dmills]

I have done (and documented) installations that deviated from 7671, no big deal, you just have to be very sure that you have thought it thru, and labelled anything that deviates from what some future sparky is expecting.

If you are not prepared to stand behind your work in a court (Or, shudder, in front of a coroner), should you be doing it?

Time was that it did not list marine locations as 'special', and you want nothing to do with TN-C-S in a marina, so we used isolating transformers to separately derive power for each outlet (With RCDs on the secondary side, post secondary earth bond connection), way outside the scope of the standard, but it worked well and we had no problems with it.

Regards, Dan.

[fourtytwo42]

I think the OP has enough information now to be able to see the potential hazards, good to have the discussion/debate

I had the idea to develop a grid tie inverter where a mains frequency transformer in a separate enclosure was used to interface with the grid. (That transformer could be a common AC wall wart for an experimental/educational setup.) The inverter circuit itself is then low voltage and far safer to work on. As a low voltage circuit, it would also not be subject to the UL requirements that apply to mains connected circuits.

It turns out, though, that for a small solar setup, it makes a lot more sense to not use an inverter at all. Still, I would like to see an open source grid tie inverter as an alternative to the cheap, unreliable Ebay units.

There are such DIY circuits available if you know where to look, low frequency transformer coupled GTI's are fairly safe to construct. The high frequency transformer type require much more high voltage circuitry and should only be attempted by the more experienced, there are a few examples on some silicon vendors websites such as TI, Micro-chip, ST & others. This comes into the same safety bracket as DIY SMPS's to me, you must understand the constructional requirements for safety, it's not just a matter of a schematic and some software
I didn't mention transformerless designs as they really do come into the dangerious arena IMOP.

[mtdoc]

"Wall-plug" grid tie inverters are illegal in the US. Full stop.

Any grid tie inverter in the US must meet UL1741 to be compliant with the N.E.C.  Wall plug inverters do not.

While I do not know the details, I'd be "shocked" if there were not similar regulations in other developed countries.

[fourtytwo42]

"Wall-plug" grid tie inverters are illegal in the US. Full stop.
Any grid tie inverter in the US must meet UL1741 to be compliant with the N.E.C.  Wall plug inverters do not.
While I do not know the details, I'd be "shocked" if there were not similar regulations in other developed countries.

I am not quite sure what drives you to keep harping on and on, there are plenty of people who experiment around including in your country so you will just have to accept that not everybody has the same black and white view of the world as yourself.

[mtdoc]

"Wall-plug" grid tie inverters are illegal in the US. Full stop.
Any grid tie inverter in the US must meet UL1741 to be compliant with the N.E.C.  Wall plug inverters do not.
While I do not know the details, I'd be "shocked" if there were not similar regulations in other developed countries.

I am not quite sure what drives you to keep harping on and on

Um - one post in this thread is "harping on and on"?

you will just have to accept that not everybody has the same black and white view of the world as yourself.

I posted some factual info. Are you disputing those facts?

I really posted no opinions - other than that I'd expect other developed countries to have similar laws as the US.

As far as people experimenting with solar PV installations.  I'm well aware of that and all for it - as long as they are not jeapordizing others safety when they do it. "Wall plug" grid tie inverters are unsafe -at least all of the ones I have seen. If one is available that passes UL1741 or equivalent anti-islanding standards (as well as other common sense safety measures), I'd love to hear about it.

 I've been personally building as well as helping others design and install small and large PV systems for several years now.

It's unfortunate that there are so many uninformed people tinkering with these cheapo wall plug grid tie inverters. Like any unsafe electrical practices - the probability of an accident may be relatively low but the consequences of one are potentially fatal.

It's sad to see someone on an engineering forum promoting such practices to the naive.

If your are truly interested in things "green/eco" as your profile says and DIY then you should be interested in things being done safely.  All it will take is one accident involving a utility worker during a grid outage to give ammunition to the anti RE crowd for banning PV installations or outlawing any DIY installations.

[Gyro]

"Wall-plug" grid tie inverters are illegal in the US. Full stop.
Any grid tie inverter in the US must meet UL1741 to be compliant with the N.E.C.  Wall plug inverters do not.
While I do not know the details, I'd be "shocked" if there were not similar regulations in other developed countries.

I am not quite sure what drives you to keep harping on and on, there are plenty of people who experiment around including in your country so you will just have to accept that not everybody has the same black and white view of the world as yourself.

On the contrary - reading back through the past page, it's you who keeps "harping on" about legality, despite solid documented evidence contradicting your viewpoint! Maybe it's time you started citing something factual rather than your opinion.

But it's still illegal in most other countries.

Really, well its not illegal in my country, name some of these "most other countries" where you think it is and while you are at it perhaps you could enlighten us with your location ?

[fourtytwo42]

I don't think there is any more point in corrupting the OP's thread with a load of small minded rubbish!

[Simon]

Can we calm down. Personally I would expect ebay to prevent listings that are illegal in the destination country but I'm not banking on it. Personally I have a 1.5KW system plugged into the wall, yes plugged in. it is a sunnyboy inverter, I would never trust those chinese ones without a lot of proof, there is a reason why the likes of sunnyboy are more expensive and unless you are putting in at least 1.5KW its not worth it.

[mtdoc]

Personally I would expect ebay to prevent listings that are illegal in the destination country but I'm not banking on it.

They don’t.

Personally I have a 1.5KW system plugged into the wall, yes plugged in. it is a sunnyboy inverter, I would never trust those chinese ones without a lot of proof, there is a reason why the likes of sunnyboy are more expensive and unless you are putting in at least 1.5KW its not worth it.

I had no idea SMA made a grid tied inverter that connects to the grid by simply plugging into a wall socket. Model number or link?

[Simon]

Err you can pug a plug on the end of any wire on anything. I didn't say they put that in the instructions. I live alone so its not a problem for me. it was just a lazy way of installing it. Legally in the UK I'm not allowed to do my own wiring anyway.

[f4eru]

Yeah, let's build a dangerous appliance.
Like, that's a great idea, and a really good advice to give to others......

[Simon]

I'm not sure what you are referring to. As I alluded to above what one does for oneself one might not do on a commercial basis, but on the other hand given the risk to life would I trust some no name unit from china just because they self certified it as CE? hell no!

[f4eru]

I'm referring to that :

you can pug a plug on the end of any wire on anything.

Dangerous advice.
Dangerous for yourself, for other people around you, for people who will follow that kind of advice, and the people around them.

[Simon]

I'm referring to that :

you can pug a plug on the end of any wire on anything.

Dangerous advice.
Dangerous for yourself, for other people around you, for people who will follow that kind of advice, and the people around them.

What on earth are you talking about. We have all already advised not to trust dubious units from china that DO come with a plug on. My comment was in reference to a fully qualified and tested sunny boy inverter. Guess why we have regs about this and anti islanding...... its to protect electric board workers in the street that don't go knocking on doors every time they turn the power off to see if someone has a GTI installed and they certainly don't want to be electrocuted by a GTI on a sunny day that is PERMANENTLY connected to the grid..... As has already been stated, we are talking about the mains here and only those knowledgeable enough should be touching this sort of thing and don't buy a cheap GTI from china that does simply plug into the wall.

[Malvineous]

I'm a bit late to this thread but have been wondering about those cheap wall-plug Chinese grid-tied inverters as well.  I just watched Dave's video about the paltry 6c/kWh feed-in tariff he gets, and the thought crossed my mind that by feeding in the power through the wall, you'd be effectively increasing your feed-in tariff to equal what you pay for electricity, assuming you have an electricity meter that can run backwards in the event you generate more power than you're using at the time.

However some research on this showed that here in Australia, it seems that it is not permitted to wire up grid-tied power sources in this way.  It seems like you need two separate meters.  I found a story of someone who had their professional solar system installed this way and their meter was running backwards, and their energy supplier's billing system could not cope with a negative difference in meter readings and consequently they ended up with a massive bill, which took some sorting out and ended up with them having to get the system rewired properly.

So it sounds like if you were to use such a system in Australia, you'd have to be careful to make sure that overall you used more power than you generated so that each meter reading showed some increase from the last, otherwise you might get unwanted attention from the electricity retailer trying to work out why you aren't using a feed-in tariff like you're supposed to.

I can't find anything about the legality of the units themselves, but I wouldn't be surprised if it's the same as unapproved POTS telephone equipment - it may not illegal to buy or possess, but it is to connect it up to the network.

EDIT: Found this explanation which includes some info from an SA Power Networks document:

Customers are also reminded that they should not connect an SEG [Small Embedded Generator] to a mechanical disk type meter.  This will cause the meter to turn backwards giving the appearance that a customer has consumed less energy from the grid than they actually have.  This is considered to be a breach of section 85(1)(b) of the Electricity Act of 1996, as the exporting of energy interferes with the meter's ability to correctly measure the consumption of energy supplied and used by the installation connected to the Network.  Civil penalties up to a maximum of $10,000 or two years imprisonment can be applied in these situations.

That page also explains that modern meters (those with digital readouts) will count exported power the same as imported power, so using 1 kWh and feeding back 1 kWh will show as if you've used 2 kWh total, so you'll be billed for both the power you've used *and* the power you've exported.  So if you have a digital electricity meter, one of these plug-in inverters will cost you more than not using it.

[fourtytwo42]

Different electricity meters behave differently when presented with reverse power flow, some count it the same as forward power, some dont count it all, and rarely they count backwards. Many will light a fraud led that is liable to trigger an investigation next time your meter is read. The best way is to either ask your electric company or search for the meter model number on the web to find it's charecteristic. The nature of the source of the reverse power is irrelivent as far as the meter is concerned. Here in the UK I was lucky enough to find a site where all the commonly fitted meters were listed along with there "export" compatability, could I find it to post you a link.....not!! In any case not much use in Aus

[David Hess]

What a way to encourage the adoption of solar.  Some areas in the US play the same game.

[Simon]

The problem is that they will not buy it from you for the same price they sell it to you for. This partly justified as they have to maintain the cabling although in reality anything I quietly dump into the grid won't have to travel that far..... In the UK it is like AUS at the moment at 4p/KWh while you can pay between 12 and 18p/KWh to import. given the ripoff and that my roof is not facing the right way I just stuck 1.5KW of panels in my garden and plugged a sunny boy into a socket. I have not had problems yet although my supplier can't read my smart meter yet but I doubt a problem will arise. my monitor shows negative power but I doubt the meter is counting it backwards.

[DougSpindler]

I’m surprised no one has mentioned how dangerous this is.  Not for the OP, but for utility workers.  If inverters are tied to mains, they can back feed and kill untility company workers. SS

[Simon]

I’m surprised no one has mentioned how dangerous this is.  Not for the OP, but for utility workers.  If inverters are tied to mains, they can back feed and kill untility company workers. SS

In the UK the limit is 4KW apparently something to do with this but not sure how. Proper GTI's - not chinese garbage would have been properly designed for this.

[fourtytwo42]

I’m surprised no one has mentioned how dangerous this is.  Not for the OP, but for utility workers.  If inverters are tied to mains, they can back feed and kill untility company workers. SS

If you read the thread you will find someone who didnt know what they were talking about already mentioned this, provided the grid tie is properly designed and meets the relevent standards no such danger exists and I for one have never heard of a grid tie that did not meet these requirements. Please dont obscure the point of the thread with fluff.

[mtdoc]

I’m surprised no one has mentioned how dangerous this is.  Not for the OP, but for utility workers.  If inverters are tied to mains, they can back feed and kill untility company workers. SS

If you read the thread you will find someone who didnt know what they were talking about already mentioned this, provided the grid tie is properly designed and meets the relevent standards no such danger exists and I for one have never heard of a grid tie that did not meet these requirements. Please dont obscure the point of the thread with fluff.

The danger is real. There are many “wall plug” inverters sold on ebay, etc that do not meet UL 1741 or any other anti islanding standards and absolutely no “wall plug” inverter that does meet those standards.

Modifying a properly designed and certified inverter so that it can be “plugged in” is not the same thing.

[DougSpindler]

Just saying one good be back feeding to the grid and kill someone who thought the grid was dead.

[DougSpindler]

Here’s the othering to think about when illegally backfeeding to the grid.  If you do happen to kill someone I’m sure you would be charged with murder.  And I’m sure your power meter would make a good witness against you.

[fourtytwo42]

Here we go again another load of mindless trash, you people are so busy bieng self righteous you dont stop to think what is the point of this thread, ohh I know it's somewhere I can be cool and make noise upon! Why dont you go back to electric cars or something 

[mtdoc]

fourtytwo42,

Your sig says you are interested in all things green/eco.   If so, perhaps you should consider taking a more professional attitude to solar PV systems. 

It is not just utility workers who are endangered by grid tie inverters without proper anti-islanding features.  Where I live, we often have wind storms that take out residential overhead powerlines when trees come down.   After a big storm it is often several days before the utility can get to all repairs. In the meantime they shutdown power to lines that are lying on the ground for obvious safety reasons..  Any improperly designed grid tie inverter feeding power to those lines is a danger to any neighborhood kids, animals or others ignorant enough to contact them.

This danger should be obvious to anyone with a modicum of electrical knowledge.   The OP of this thread was asking specifically about this danger.

There are many threads on this forum about the dangers of isolation transformers, poorly protected DMMs, etc.  Many of those threads raise valid concerns, but in other cases the concerns are overblown and alarmist IMHO.   This topic is not one of those cases. In this case the danger is not just to the equipment user, but to innocent bystanders.

[ I for one have never heard of a grid tie that did not meet these requirements.

All it takes is a quick eBay search for "grid tie inverter" to pull up >1000 inverters - the vast majority of which it should be obvious to most knowledgable  forum members are not likely to be properly designed or have any valid anti-islanding certification.   There are youtube video teardowns of several of these that confirm that point.

[fourtytwo42]

I don't wish to get into a particular spat here BUT this subgect has already been exhaustivly covered in this thread before today. Due to some recent activity the thread came to the attention of some thread jumpers who obviosly did not read it fully before restating what had already been said. As a matter of fact the first Chinese GTI I picked from your link includes the following wording "Protection:Islanding; Short-circuit; Low Voltage; Over Voltage; Over temperature Protection".

What you people are doing is preventing any sane discussion of high voltage matters by jumping on any thread that catches there eye and harping on about safety. I would expect every person here to be safety concious and any of us with experience try to guide people in a safe manner. But to stifle discussion and overload threads with copybook quotations does nobodies understanding any good whatsoever.  Personally I doubt many have any relevent experience when it comes to high voltage engineering.

Whilst I agree with your lurid picture of live wires flaying all living things within a substantial radius the likelyhood in reality is less than being hit with an errant piece of spacejunk

So lets all keep a sense of proportion and allow sane discussion rather than copybook readings of some textbook! AND please can people actually read through an entire thread before deciding to add irrelivent or repeated information. Armchair warriors in my book are a PITA!

[mtdoc]

As a matter of fact the first Chinese GTI I picked from your link includes the following wording "Protection:Islanding; Short-circuit; Low Voltage; Over Voltage; Over temperature Protection".

Right. And it has that coveted indication of safety, the "CE" rating as well.   And every cheap DMM has a perfectly valid CAT safety rating don't they?  You must realize forum members here are smarter than that, right ?

Armchair warriors in my book are a PITA!

I've designed and installed several solar PV systems over the past 10 years, including my current 4500 watt home grid tie with battery back up system. 

I've seen your posted "system".   And as long as someone stays off grid and doesn't endanger others (or endanger the reputation of solar PV) - I'm all for backyard engineer DIY solar systems.  I have a small one powering a shed on my property myself.

[fourtytwo42]

I've seen your posted "system".   And as long as someone stays off grid and doesn't endanger others (or endanger the reputation of solar PV) - I'm all for backyard engineer DIY solar systems.  I have a small one powering a shed on my property myself.

So are you accusing me of something ?

[Simon]

Here’s the othering to think about when illegally backfeeding to the grid.  If you do happen to kill someone I’m sure you would be charged with murder.  And I’m sure your power meter would make a good witness against you.

Stop being silly, why don't you contact sunnyboy about your concerns..... and is giving power away illegal? can we have some sources for that statement please.

[mtdoc]

Here’s the othering to think about when illegally backfeeding to the grid.  If you do happen to kill someone I’m sure you would be charged with murder.  And I’m sure your power meter would make a good witness against you.

Stop being silly, why don't you contact sunnyboy about your concerns..... and is giving power away illegal? can we have some sources for that statement please.

Simon, to be fair, I don't think he is referring to your Sunnyboy inverter which is, as you say, a "proper GTI"  - well designed with proper anti-islanding.

FWIW - As required by the National Electric Code,  it is illegal in most if not all jurisdictions in the US to back feed to the grid with an inverter that does not meet UL 1741 and IEEE 1547 standards (as your SMA inverter does).

The real issue is with the "chinese garbage" as you call it. That was what the OP of this thread was asking about as well.

For example this popular gem

[NiHaoMike]

There are "microinverters" from reputable manufacturers. What's wrong with getting one of those and wiring a plug to it?

[Gyro]

I’m surprised no one has mentioned how dangerous this is.  Not for the OP, but for utility workers.  If inverters are tied to mains, they can back feed and kill untility company workers. SS

If you read the thread you will find someone who didnt know what they were talking about already mentioned this, provided the grid tie is properly designed and meets the relevent standards no such danger exists and I for one have never heard of a grid tie that did not meet these requirements. Please dont obscure the point of the thread with fluff.

@fourtytwo42:

I was the person "who didn't know what they were talking about", who raised the issue of safety on page 1. I was the person who challenged and refuted your uninformed statement about UK legality of putting mains on a 13A plug, and then drew your attention to the relevant ENA and IET references (Reply #12), which you "confessed" that you had missed (more likely, had no clue about), only to be faced with your "fluff" about Illegality versus Criminal Offense.

I will not return to the argument, However - In future, choose your words with much greater care!

An apology is in order.

EDIT: According to Reply #61, I was apparently not the person who didn't know what they were talking about! 

[Simon]

Well to be honest it is up to each government to regulate these devices. The chinese stuff should be banned, ceased as the ports and destroyed.

Anti islanding I beleive is a natural consequence GTI, it is designed to follow the grid voltage, if there is no grid voltage then it drops to zero. Also if you are suddenly trying to power an entire street with 200W guess what your output voltage will be???

[mtdoc]

Anti islanding I beleive is a natural consequence GTI, it is designed to follow the grid voltage, if there is no grid voltage then it drops to zero.

Unfortunately, it's not that simple. That is what should happen of course.   And with "grid interactive" inverters or "AC coupled" home back up systems - you need the inverter to continue to work with battery power once the grid is down.

Also if you are suddenly trying to power an entire street with 200W guess what your output voltage will be???

  Sure.  But that is likely not the scenario when the utility worker is at the pole making repairs and may not be the case with trees take out powerlines.  Hence the term "islanding"

[Simon]

Anti islanding I beleive is a natural consequence GTI, it is designed to follow the grid voltage, if there is no grid voltage then it drops to zero.

Unfortunately, it's not that simple. That is what should happen of course.   And with "grid interactive" inverters or "AC coupled" home back up systems - you need the inverter to continue to work with battery power once the grid is down.

So now you not talking about GTI anymore? if the inverter is going to power the house with no mains it needs to disconnect from the mains and then restart in island mode. I have another inverter that has an island mode but even if you flick the switch you have to shut off all power to it and start again. that is NOT GTI, so the problem yoau had with GTI was???

Also if you are suddenly trying to power an entire street with 200W guess what your output voltage will be???

  Sure.  But that is likely not the scenario when the utility worker is at the pole making repairs and may not be the case with trees take out powerlines.  Hence the term "islanding"

How? if power is lost to the area due to it being cut usually as a consequence of a shorted power line, how is that different from the scenario where you have a street disconnected for regular maitenance attempting to be powered from a single 200W source? OHM'S LAW ANYONE??

[mtdoc]

Anti islanding I beleive is a natural consequence GTI, it is designed to follow the grid voltage, if there is no grid voltage then it drops to zero.

Unfortunately, it's not that simple. That is what should happen of course.   And with "grid interactive" inverters or "AC coupled" home back up systems - you need the inverter to continue to work with battery power once the grid is down.

So now you not talking about GTI anymore?

"Grid interactive" and "AC coupled" systems are tied to the grid also. But the main point about it not being simply a matter of inverters not putting out power if the grid is out (unless specifically designed to do so) holds true for the more common grid tie only inverters which is what this thread has mostly been referring to I believe.

Also if you are suddenly trying to power an entire street with 200W guess what your output voltage will be???

  Sure.  But that is likely not the scenario when the utility worker is at the pole making repairs and may not be the case with trees take out powerlines.  Hence the term "islanding"

How? if power is lost to the area due to it being cut usually as a consequence of a shorted power line, how is that different from the scenario where you have a street disconnected for regular maitenance attempting to be powered from a single 200W source? OHM'S LAW ANYONE??

Think about the utility worker up in the lift truck basket working on the pole in front of my house after a storm to restore power to the street.  Don't you think a common scenario is that there will at times, be no connection to the rest of the street/grid?

We've had several wind storms in my neighborhood that have taken down power lines at multiple locations. Any particular power line may at any time be still connected to only one, or a few homes.

[Simon]

Well ultimately a properly designed GTI will not output if there is no mains. A GTI worth it's salt and commercially sold should be certified. The chinese stuff is not very efficient and has no third party oversight and should not be allowed into the country. Last time i asked a utility company about a GTI they just wanted to know that it was CE marked....

[f4eru]

Well ultimately a properly designed GTI will not output if there is no mains.

Yep.
But it's still against regulation, against service rules from your electricity provider, against all relevant norms, and against the installation manual to put that on a male plug.
Illegal. For a reason.
Point.
Connect it correctly. Don't play with people's life just to save a few euros for correct installation.

[DougSpindler]

There are "microinverters" from reputable manufacturers. What's wrong with getting one of those and wiring a plug to it?

If you want to wire a plug to one go right ahead, just as long as your aren’t connected to the grid.  As has been mentioned in previous posts if you are backfeeding into the grid could be endangering the lives of utility workers, small children and the community where you live.

Just think how you would feel or how people in your community would feel if you were backfeeding to the grid and there was a down power line and your system electrcuited to death a small child.

And please don’t say something like this might not happen.  Auto accidents and storms where I live have all resulted in downpower lines.  When playing with HV electricty isn’t it better to be safe?   

[NiHaoMike]

Those microinverters from reputable companies are designed to be safe to connect to the grid. Not the Ebay specials that are built for the lowest price and questionable in just about every way, but a proper unit designed to meet safety requirements.

[Simon]

There are "microinverters" from reputable manufacturers. What's wrong with getting one of those and wiring a plug to it?

If you want to wire a plug to one go right ahead, just as long as your aren’t connected to the grid.  As has been mentioned in previous posts if you are backfeeding into the grid could be endangering the lives of utility workers, small children and the community where you live.

Just think how you would feel or how people in your community would feel if you were backfeeding to the grid and there was a down power line and your system electrcuited to death a small child.

And please don’t say something like this might not happen.  Auto accidents and storms where I live have all resulted in downpower lines.  When playing with HV electricty isn’t it better to be safe?   

So are you trolling? it "backfeeding" as you call it is how every GTI works including every "official" installation of a GTI, do you accept that or not? or are you just trolling??

1) You can come up with evidence
2) You can just leave if you have no further information to add
3) Do I actually need to consider action for your trolling?

This discussion has become pointless because no one is offering evidence to their statements that they keep reeling out like a broken record. Earlier you said it is illegal, show me the law or go away!

[Gyro]

Simon, if you want actual evidence then please refer to BS7671 IET Wiring Regs, 17th Edition (551.7.2 (ii)), which I linked way back on page 1.

https://www.scribd.com/presentation/259597021/17th-edition-overview-ppt

I agree, most of what followed is unsupported opinion.

For ENA G83 rules on grid tied inverters <3.68kW, the power rating likely covering all wall plug inverters (13A plug fuse), the link is below (again).  I will leave you to judge whether the Chinese inverters commonly on sale meet the G83 rules. Note that this is secondary to the IET regs above in any case...

http://www.energynetworks.org/electricity/engineering/distributed-generation/distributed-generation.html


EDIT: I will leave it to others to locate and post the relevant wiring regs reference for the US (OP's location).

[fourtytwo42]

What a shame this forum has descended into chaos! Anybody reading this and wanting to learn anything would probably conclude this forum is to be avoided. The person who thinks they deserve an apology is not the person I was thinking of (as I don't recall them making unsubstantiated claims) and I cannot imagine why they think they deserve one.

Adios

[Simon]

Simon, if you want actual evidence then please refer to BS7671 IET Wiring Regs, 17th Edition (551.7.2 (ii)), which I linked way back on page 1.

https://www.scribd.com/presentation/259597021/17th-edition-overview-ppt

I agree, most of what followed is unsupported opinion.

For ENA G83 rules on grid tied inverters <3.68kW, the power rating likely covering all wall plug inverters (13A plug fuse), the link is below (again).  I will leave you to judge whether the Chinese inverters commonly on sale meet the G83 rules. Note that this is secondary to the IET regs above in any case...

http://www.energynetworks.org/electricity/engineering/distributed-generation/distributed-generation.html


EDIT: I will leave it to others to locate and post the relevant wiring regs reference for the US (OP's location).

A statement was made that it is ilegal to back feed into the grid which is exactly what any GTI system does, so if there is a law in this regard sure. As I have ALREADY said the chinese stuff that does not meet the standards should be destroyed on docking but UK authorities are at best a pushover and basically absent  so you can sell any crap to the UK. If it's illegal it should not get through customs, what else do we pay a tenner a go for?

[DougSpindler]

This forum is for leaning and educating.  In the United States as is the case in other countries it is illegal for one to attach a solar system tot he grid and back feed unless the equipment has been permitted and inspected.  The reaso is safety.  Illegal back feeding is what we have been talking about with unapproved, uninspected equipment. 

You had better believe if someone is illegally backfeeding electricty to the grid and someone is electrocuted to death, especially a child that the DA will charge the back feeder with murder. No licensed electrician would ever endanger the lives of others....  But someone who doen’t know what they are buying or doing just might.

I hope others who read theirs in an attempt tp learn realize just how dangerous illegal backfeeding can be.  There have been many a Darwin Awards awarded for people “playing” with electricity.

[f4eru]

One problem that doug describes is taking an unsynchronized inverter, and feeding it through a socket into the house's network, which is a big no-no
(extremely dangerous & illegal)
This one seems to be a common bad habit for some people in the US.

The other problem is taking a GTI, and connecting it through the same male plug to the grid.
Also dangerous  & illegal
This one seems to be a bad habit for some people in the EU according to some in this forum.

[Gyro]

What a shame this forum has descended into chaos! Anybody reading this and wanting to learn anything would probably conclude this forum is to be avoided. The person who thinks they deserve an apology is not the person I was thinking of (as I don't recall them making unsubstantiated claims) and I cannot imagine why they think they deserve one.

Adios

In that case, I may have been premature in assuming that you were referring to me. My apologies. 

[NiHaoMike]

The other problem is taking a GTI, and connecting it through the same male plug to the grid.
Also dangerous  & illegal
This one seems to be a bad habit for some people in the EU according to some in this forum.

Is the concern that the inverter may put a dangerous voltage on the exposed pins when unplugged from the mains? A case that all grid tie inverters better than the questionable Ebay specials are specifically designed to avoid? I'm not sure if any reputable grid tie inverters check for continuity between neutral and ground but I don't see much reason to not do that as one of the basic safety checks.

It's worth noting that in the US, mains plugs are not touch safe when partially inserted. I'm surprised that in over a century of use, no addition has been made to solve that flaw.

[f4eru]

Is the concern that the inverter may put a dangerous voltage on the exposed pins when unplugged from the mains?

That's one concern. the check of the grid presence may not be guaranteed, even if it should be, or the detection time may be too long, so if you touch the prongs too early before disconnection, etcetcetc...

The other problem is that it is not designed to run like this. There are fundamental normative and safety differences , protection schemes, for an equipment which has a wall plug than an equipment connected permanently by an electrician. The GTIs are not designed and not approved to be connected on a male socket.

[Simon]

One problem that doug describes is taking an unsynchronized inverter, and feeding it through a socket into the house's network, which is a big no-no
(extremely dangerous & illegal)
This one seems to be a common bad habit for some people in the US.

What have you been drinking? how on earth can anyone contemplate putting an inverter into the mains that is "not synchronised" in otherwise NOT a GTI. The only person that would be harmed would be the idiot plugging it in to a live grid as it would blow up possibly pirotechnically. Your statement demonstrates an amount of ignorance or intention to keep this discussion below the intelligent line.

The other problem is taking a GTI, and connecting it through the same male plug to the grid.
Also dangerous  & illegal
This one seems to be a bad habit for some people in the EU according to some in this forum.

Yes using a male plug is technically incorrect, I had an electrician doing work in my house and he congratulated me on my ingunuity, he did not give me any "advice". Theoretically the inverter goes dead the moment it is unpluged as per the very nature of a GTI and as regulations dictate that I'm sure the SB1700 is made to, no one else lives here. I also have it connected through an RCD so there is no real chance of anyone being harmed. I am still waiting for references to the specific law. I think the reason most systems are inspected goes back to when panels were expensive bu the FIT was 4x the going rate, some smart arse could declare to have a solar system and just hook up a petrol/deisel generator

[f4eru]

What have you been drinking?

One glass of wine, thank you very much.

how on earth can anyone contemplate putting an inverter into the mains that is "not synchronised" in otherwise NOT a GTI....  plugging it in to a live gri

I never said the grid is live.
They feed their house though a socket. Total morons.
Google "suicide cord", you'll find all the details.

[Simon]

Oh so you have found out about one particular idiot that did something stupid and now even legit technology should be banned? No you show me your evidence. This thread is full of hot air from people who don,t seem to get which particular subject is being discussed.

[f4eru]

legit technology should be banned

I never said anything remote.

[Simon]

legit technology should be banned

I never said anything remote.

Well some people here are advocating that the use of perfectly legit stuff (made and sold by reputable companies to standards) is illegal, at every reply we get a new crazy assertion with nothing to back it up!

I think it is time to lock this thread. I have repeatedly asked for proof of outlandish claims and all we get is more outlandish claims. If similar happens in future threads banning will be considered, we seem to be spiralling into forum wide trolling of just about anything!