Before Buying Plug-in Grid Tie Inverter Watch This Video - Safety Warning
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- Опубликовано: 7 сен 2024
- In this short presentation, I explain one of the biggest risks to using a plugin grid tie inverter (GTI) or grid tied solar inverter. I created a grid tied wiring diagram with simple graphics to explain the risk.
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Grid tied solar is a lot of fun and very rewarding for the user. But this type of grid tie solar inverter will incur certain risks, and if the homeowner is not aware, could result in a catastrophe. Many people purchase and use grid tie inverters without any awareness of the safety risks and little to no understanding of what they're up against. Grid tie inverter installation can be very quick and easy but safety should never be compromised. I hope this video helps someone, and that they learn something useful about grid tie solar setups before starting their build. Understanding the video subject is of critical importance before purchasing and using a grid tie solar inverter (more so the plug-in type, but technically could still apply to hard wired setups)
If you have any questions or comments, please feel free to let me know, and if you would thumbs up and subscribe it would be greatly appreciated. Thank you for watching, DDSolar
#gridtieinverter #gridtie #solar grid tie #gridtiedsolar #safety #safetyfirst
As a complete noob to DIY solar, I found this very concise and useful. I understood it the first time through, because of the simple diagram, and it makes perfect sense. Thank you for taking the time to make this video :)
You are very welcome! Glad to hear it, thanks for the good feedback :)
Good thing you’re pointing out the problem of a multi-location feed onto a branch circuit. I’ve watched several videos of people never mentioning this problem, only encouraging others to do it to backfeed solar power.
@kamakaziozzie3038 Indeed... hoping this video will warn enough people, they will spread the word and be more cautious
I have been searching for this for days. Thank you.
@seanyounk1 Welcome sir! :) 👍
Good point. Obvious now you point it out, but I had never considered that!
Thanks the risk was bothering me for a long time so I made this vid. Figured I'd spread the word around. Thanks for watching :)
Sounds like the safest way to do this is to install a dedicated 20 amp breaker in the breaker box, then a run to a new dedicated socket, and plug in the inverter there for the entire house?
That's absolutely correct, also I believe this is what electrical regulations generally require or recommend.
GREAT INFO
Thank u sir
This has been a topic I've been trying to figure out for a while I've been trying to figure out on a 240 can I convert it for solar or use a plug-in inverter since the circuit only has two plugs and only one of them gets used overnight.
@briansiebert8523 With only 2 plugs on a circuit, one for the inverter and one for the appliances, I guess it's a lot less likely to have any kind of problem
One issue that has stopped me is the neutral ground bond. Code says it needs to happen at the power source. Now your introducing a new power source without a N+G so therefor you will not be protected.
Definitely a concern, hope maybe I can address this in a future video
Sure you will be protected because the ground, live and earth are still connected to the main power distribution. When there is a leakage or connection to the earth wire, the main fuse(s) will trip and the GTI stops automatically when there is no main power available (heartbeat of the system, 50/60 hz).
This guy is great, but if you dedicate a single circuit with a 10gauge wire 30a breaker for a 25 amp inverter with nothing on it except the inverter, that feeds the main buss it changes up the concern of the single circuit. It does make me question the end of the systems transformer, that is on the utility end.
Hopefully the buss bars can handle it, I figure they are good for a few 100s of amps at least :)
great info , all true
Thank you :)
Hi, nice video and some fair points made.
From the comments I see that it is acceptable to hard wire into a spare breaker. But I am wondering if this is correct.
I have a 63A main breaker and then all my individual breakers are 20A or 16A. If I hard wired a GTI into my spare 20A breaker then wouldn't that technically be adding another potential 20 Amps for my main breaker to handle in the same way you described for the outlets in an individual circuit?
@Ulbre Hello and thanks! Good question. Hard wiring your GTI into a dedicated 20a breaker is just fine, as long as the wiring from the breaker to the GTI can handle the current. With regards to the main breaker, it can't flow more than 63a into the panel in theory. If it's using 63a from the grid and then you backfeed 20a from solar, it drops to 43 - no problem either. If you add up all the breakers in the house and they exceed 63a, there is a chance it may trip some day. But I don't think it will harm anything.
@@solarpoweredge Thx so much for your swift and detailed reply. I will be checking out your video library where I am sure I will learn a lot. Wishing your channel a heap of success :)
@Ulbre Very welcome! glad you are here, thanks for watching :)
Thanks! Very good info, I have subscribed. Question: Would the problem be avoided if there is a 15a breaker between the GTI and receptacle it's plugged in to? Or maybe a GFI receptacle where the GTI is plugged in?
Welcome and thank you very much for subbing :) If a GTI was feeding 15A in through its own 15A breaker and then on into a shared branch circuit which also had its own 15A breaker for the whole branch, it could still defeat the branch's breaker and thus overload the wiring in the wall. Each breaker could theoretically feed 30A combined into the branch wiring. So it is incredibly important to always use a dedicated circuit for the GTI, and resist the tempation to plug into any convenient outlet on a shared branch circuit. A dedicated circuit 100% avoids this pitfall as well as others. I am sure many GTIs end up on a shared branch anyway - but at least people will be aware of the dangers involved and make a more informed decision. In the future I plan to do a more thorough presentation on GTIs. Hope this helps - DD
So could you just tie into the breaker 1/4 of my house is dedicated to one breaker . I was thinking if I could just go solar and tie in to the 1/4 my bill would drop
@lilrararesales270 Is there a space in the breaker panel for a dedicated circuit? That would be the safest way to proceed. If you decide to backfeed into an outlet (existing breaker), I recommend keeping the power 500w or less.
this is pretty much a textbook situation on how people get into trouble.... especially now that 1,000 watt and larger systems are available these days. BTW, a 15 amp branch circuit is only rated to carry an 80% load long term so now we're talking 12 amps continuous, which is around 1,400 watts. The 15 amps is actually for 3 hours or less. (intermittent draw)
Hi, right on. It's the code requirement I believe and a sensible one. In my profession we call it the 80/20 rule. It's usually possible to draw 15A continuous from a 15A circuit but you never know the condition of the breakers, outlets, wire nuts, and who knows what else is hiding in that wall, especially an older building. How many years of drawing 15A before something in the wall gets a bit too hot and fails. Pretty risky. This video did omit detail in an urgent attempt to reach the layman quickly before he "clicks something else". Tried very hard to keep it simple so people would get the most urgent concept asap. I really hope those who are looking at plugin GTIs will do a lot more research about electrical topics after seeing the video. Thanks for watching :)
@@solarpoweredge ... I just retired from 25 years in the generator business, and you'd be amazed at what DIY people think they know when it comes to a simple project. Some of them shouldn't be allowed to change a lightbulb.
@@rupe53 Cool, man across teh street retired from his generator shop, he has a lot of cool equipment. And of course a whole house generator setup.
@roberto lang ... I was both born and retired in the US and my comments are about the safety aspect because the laws of physics don't change from one country to another. What I am trying to say is some things may work, even though they are not really safe. That's why we have rules and building codes.... and they may be different for a reason that's not always clear to the average guy.
@@solarpoweredgeI had a plumbing company install a new electric heat pump water heater. When I came home next day from work the water was cold the breaker was tripped. I assumed the water heater failed shorted out maybe the compressor its a heat pump. I turned the breaker back on see if it would trip again, it didn't. I went in the house came back out saw a burn mark up the wall where the flex conduit went into a 2 Gain box. When I removed the wall plate entire box was black with soot the feed wire was gone. My house has aluminum wire the 240V wire had burned up what he did was wire nut copper wire in the whip to aluminum wire with yellow wire nuts. Previously the water heater had an old school pool timer where AL and Copper wire were not wire nutted. The wire had burned up into the wall stopped where strain relief was on the box inside the wall. I was lucky if it didn't get enough current to trip the 30amp breaker could have burned entire house down. I had the company install a disconnect box above the water heater so there are no wire nuts. Your right that can burn down a house without tripping a breaker. Newer houses I know have arc fault maybe that works better but I'm not sure it's required on 240 circuits.
Thank you!
Welcome!!! :)
We have the 2000 watt version however it stopped working do they have an internal fuse it says lifetime warranty what's the page on Amazon disappeared thank you in advance
@actionnew Hello, I think there are fuses inside. Might want to check the solar input side to see if it's shorted. If you know anybody that can repair inverters, they can probably take a look at it.
@@solarpoweredge there are DC fuses but they are good. . thse units have been removed from Amazon since many have failed..
@actionnew That's not good. I hope they fix the problem, I kind of like these inverters.
If it's a shorted MOSFET it can be replaced, a very common task. But otherwise, could be a more complicated problem. Inverters are not fun to troubleshoot and repair. Might just want to keep it in case there is a way to repair it later on.
@@solarpoweredge it appears u have to take out each mosfet eh...... to test them .
@actionnew Yeah... not too fun
What if you have dedicated breaker for inverter. Land wires from inverter straight to breaker box? No other load could be on the line.
Yes that's a good idea
Very interesting video, thank you. What about using a circuit barker between inverter and house socket?
Mmmm no i don't think that would work....
Actually it's an interesting thought, limiting the power output before the wall. Maybe if you keep track of and control everything plugged into that circuit. The (safest) route is generally a dedicated circuit so the existing breaker is guaranteed to trip. This is very inconvenient though because a dedicated circuit may not be near the inverter.
Forgot to say, you're welcome and glad you liked the video. It's a rather obscure topic but of utmost importance for plugin grid ties
No. To be safe the sum of all the currents must not be greater than the breaker box breaker rating. In the video example placing the GTI at the beginning of the branch circuit (1st outlet down stream of the breaker box) demonstrates a scenario where the currents sum in the wire towards the loads. However, if the GTI is plugged into the end of the branch circuit, less current flows in the wire upstream. Though I think you are still asking for trouble. If the GTI breaker trips, or batteries feeding inverter run down, all the current comes from the breaker box, though it "should" trip the breaker in the breaker box. Moral of the story, don't overload the branch. KISS principle applies, do as @solarpoweredge says :)
@@MarcFain Thank you for your interesting reply.
If I already have net metering Solar sending back power to the grid do I need to use the limiters?
Can I just run it without the limiters?
Is there a down side to running it without the limiter clamps?
The limiter clamps are for those who don't want to "back feed" into the grid, but only supply household loads. If you only use 100w, the inverter throttles down and produces 100w. If you want to use net metering and feed excess power back, the clamps are not really required. No downside really. Hope that helps. DD
Good info.
Thank you :)
Interesting; had same thoughts with AC and grid-ties. AC being a bit odd with it reverse direction every 1/2 cycle makes my little brain hurt.
So really you'd want 15amp fuse or breaker inline on each side of back feed outlet if you "really" wanted to do this safely. This would always keep electrons moving less then 15amps on each side.
I often wondered; is there a problem with backfeeding only 1 leg of the panel. Should the setup be 120V and feed two breakers equal current and/or 220V so you are getting both legs. Backfeeding just one side of phase seems wrong on surface; but eh... maybe not an issue.
This stuff taxes my brain as well. I had to give it a lot of thought before I stopped worrying about it. In my opinion feeding half of 240V in an active household electrical system is fine, provided the GTI has a dedicated circuit. A dedicated circuit completely bypasses any question of overloading the house wiring. All you're doing is feeding some synchronized AC into the house to carry part of the load. What I never do is backfeed to the utility. I only use the GTI to help supply my house, the rest of the power comes from the grid. Always done it this way and besides the utility doesn't pay a high enough rate for that expensive solar power anyway.
what about a dedicated 15/20 amp outlet for the inverter for lower powered solar arrays around 1k-1.2k?
Yes definitely good enough. If nothing else is plugged in, the circuit shouldn't be overloaded by that amount of Watts
@Solar Power Edge ok good this was my plan with a tiny home build but got worried when I seen this video lol
I hear you lol I get pretty worried about this stuff. But with a dedicated circuit, no problem at all.
If plug and play inverters are so dangerous, how could some get UL 1741 certification?
My question would be, does any certification eliminate the danger of a GTI backfeeding a shared branch circuit, and overloading conductors hidden in the wall without the user's knowledge? That is the principal risk this video warns about. I believe knowledge can increase safety. I am for plug-in GTIs, but against as many house fires as possible, lest we lose access to this type of technology "for our own safety". I've seen enough plug-in GTIs burn themselves up and plenty of folks plugging them into non-dedicated circuits with zero electrical knowledge or understanding of the risks to their home and family. So I decided to warn as many people as I can.
@@solarpoweredge "Eliminate" is a strong word. But, yes, UL certification is as legit as it gets. They are collectively 1,000x more geeky than you or me when it comes to this stuff. They have anti-islanding, built-in ground, automatic shut-offs, and do not work if the grid is shut down. I understand your concern theoretically, but you would have to point to damage, fire, explosions, injury, something would have already been reported. Even the million plug and play uncertified GTIs sold are pulling it off safely, or the devices shut down. I have heard about a 1,500 watt limit to backfeeding the grid, but yeah, it is very weird, which is why I bought it and why a posse of ten electricians, including several city inspectors, rolled up on me last Friday to observe the unicorn that a UL certified plug and play microinverter is. Too cool for school. Fight the Power!
Hello, thanks for the reply. I don't believe eliminate is a strong word in this case. I think we have fundamentally different viewpoints of how a DIY person should conduct themselves. The way I see it, even though there are authorities and certifications, the end user needs to watch their own back, do their own research, and look out for their own household.
Frankly, this video is a polite attempt to warn people who backfeed shared circuits, that they need to be knowledgeable about what is ON that circuit at all times. Of course each man can do whatever he wants with his wiring. But I always recommend a dedicated circuit. Hardwire if possible, but there are a lot of plugins out there.
The fact is, overloading the wiring in a house with a plugin GTI is a fire risk, and pretty easy to do if uneducated - end of story. This is basic electrical knowledge and use of logic. It is a fact that the circuit breaker can be defeated and not trip while pushing too many Amps, as explained in the video. It ought to be common knowledge. No amount of geekery by UL is going to change that. No certification can eliminate the risk of plugin GTIs overloading residential wiring. The risk is eliminated by end users being fully educated and exercising due diligence, rather than appealing to authorities or trusting design engineers to keep them safe. Due diligence IS the first line of defense. My advice has been, don't plug it in without being educated about branch circuits and how plug-in GTIs work.
The end user needs this type of knowledge so they can exercise due diligence. My channel is about sharing knowledge to help such people. It is a fact that a plug-in GTI cannot detect such a condition as presented in the video. It is a fact that no certification prevents someone without electrical knowledge from overloading a shared circuit. It is very easy to do, just one slip up, and the risk of fire is high. The wires are hidden in the wall usually, if someone overloads them it might be awhile before the problem is discovered... or worse, too late. The breaker won't protect them as explained. If not the #1 reason for using a dedicated circuit, it's got to be at least top 3. In fact a dedicated circuit is part of meeting code requirements anyway.
I don't need to point to any particular fire report to establish the fact that the issue explained in this video is a fire risk - anyone who knows electrical can see the problem. Personally I have some experience with other plugin GTI users and fires (or sometimes just melted wires) and no they weren't going to report anything. Sometimes it's outright carelessness, other times it's "oops made a mistake, I'm gonna learn my lesson and be more careful".
I am also sure running around with scissors is a bit unsafe, but once again, don't need to find any stories about the risk. The risk is just there, and people need to know about it BEFORE they start backfeeding random outlets in their house.
@@solarpoweredge I understand the theory of using a dedicated circuit for plug and play grid tie inverters. However, one expert at Missouri Wind & Solar suggested the opposite, i.e., to plug it into a busy circuit. As for the circuit breaker being able to handle the backfeed, it makes me wonder if these new circuit breakers with AFCI and GFCI can detect problems in the reverse direction. A lot of renewable energy is going to be in an infancy stage for a while. If one tries to figure out if a horizontal wind turbine is more efficient than a vertical axis, there is a wide disparity of opinions regarding technology that has been in use for thousands of years. My GTI is not supposed to work without being plugged into the grid, but when the inspector and electricians and I put a multimeter on the plug (when unplugged) it was a bit hot. Sometimes it is hard to know who to trust these days. Thanks for your input and analysis.
Good points all around. And very interesting to find an offline inverter putting out anything, I hope it wasn't full voltage.
On the GFCI, that's a good one. The manufacturers probably don't want to talk to us GTI users. Sounds like a video topic. I've not yet found anywhere it is addressed in detail.
Just a guess at MWS'' reasoning; possibly to make sure the energy from the GTI gets used up by existing loads in the house first, so no backfeed. Incidentally I would practice such a thing - but not at the circuit level. Instead, I'd connect the GTI (example 750w) to the 120v leg which has the heaviest loads on it, in effect "propping up" that leg. Example, L1 has 1000w of 120v air conditioners or resistance heat, L2 has 150W refrigerator. So feed 750W 120v into L1. The voltage increases a bit on that leg. There is no backfeed to the grid at all, just to the loads in the house.
If someone asked me, I'd strenuously suggest a dedicated circuit whether trying to balance L1/L2 or not. We can probably assume everyone backfeeds into whatever outlet seems most convenient at the time. I do hope they'd watch my video first, because then I've done my part :)
I have a 2kw inverter. They need t be hard wired into a braker at 15 amp 220volts.
Also I use a limit system with a battery bank.
Nice setup. 2kw is serious power. I have 3x 1kW with the 4th going online hopefully soon.
I'd be interested in seeing what you have to say about 120V vs 220V GTIs. 120V can only feed one phase. Can a 220V GTI dynamically allocate power to whichever phase is calling for it, or is 50% of the power reserved for each phase? I'm assuming 220V loads will subtract evenly from the power available to each single phase. Wondered this as I read the comment by @penrodautorepair3170
That's a really good question. I have only used those 120V Sun GTIs, do the 220V versions output single phase? I'm not sure they're meant to be used with American split phase. I suspect they're single phase since that'd be cheaper. If that is the case, I don't think the inverter would even know what was going on, it would just output 220-240V 60Hz single phase and the give or take would be up to the house loads, grid and power company (the true source, the GTI just helps). This is how I visualize it anyhow, might benefit or perhaps I just make things worse!
yea... was wondering same; how I ended up at this video. Let us know if you find any details.
I was thinking just 4 solar (400w) panels on 120V@15amps 1 side of panel / 4 solar panels on 120V@15amps on other side of panel will get me close enuff.