How do you know? In a typical solar system, you have to have a permit, which requires an inspector to come out and ensure everything is configured correctly and safely. These don’t require any permits, which is great for making them more affordable and accessible, but there’s also no one coming around to make sure that anyone is doing it safely.
Inverters in the US are all listed to UL1741-SB which dictates that they shall cease to energize their AC outputs if they sense an absence of grid voltage.
Now, one thing people are ignoring is that UL1741-SB allows for islanding protection, and the disablement of it. If an inverter has its settings changed such that islanding protection is OFF, then the inverter will keep sending power to the “grid” because it thinks it’s operating on a microgrid that was previously disconnected from the larger grid via a Microgrid Interconnection Device (MID).
The settings these inverters have are user-settable, which means they need to be checked by a qualified person, either a contractor, engineer, or inspector. These settings must also often be checked by the utility you’re interconnecting to before they allow you to energize, so usually all of these parties have eyes on the inverters’ settings and can stop work before energization until things are corrected.
Ultimately I agree with you. If we don’t want to have to need inspections for every solar installation, especially residential ones and especially where plug-and-play solar modules are used, then inverters need to have their settings pre-configured for the grid code in the factory that then cannot be changed by the user or operator in the field. That would be a way to shoe-in this kind of installation.
Hard setting grid codes into inverters prior to shipping to site might be overly conservative though, especially as utilities change their grid codes over time. You need to have a way to update those settings, which could be using a wireless portal hosted by the inverter OEM with credentials made only available to the OEM. Problem with this is that then you shift the burden of configuration to the manufacturer which already has a ton of other UL standards as well as rules and regulations to follow.
I agree with everything you said except shoe-in, because it’s shoo-in.
But you articulated (better than I was going to) the number one issue. Power companies need insurance and their insurance will be affected if ordinance permits basically unchecked generators being plugged into the grid. And before anyone says it, you are not allowed to just plug your generator into your house. Does it happen? Yeah, people have been dumb since day one.
But there are transfer switches that allow for this operation in a safe manner, and the easiest way to deal with this is to have them installed by default in new construction, and to provide incentive for upgrading your panel to include one.
Inverters in the US are all listed to UL1741-SB which dictates that they shall cease to energize their AC outputs if they sense an absence of grid voltage.
No, they are absolutely not. I don’t know where people are getting this idea. Many inverters aren’t even UL listed. There is absolutely no requirement for them to be. If that were the case, off-grid inverters wouldn’t even be allowed to exist. I own several that do not have this capability and are not UL listed.
they need to be checked by a qualified person
Not in the case of Utah’s new “balcony solar” laws. That’s the problem.
which could be using a wireless portal hosted by the inverter OEM with credentials made only available to the OEM
Oh goodie, I’ve always wanted DRM for my inverter.
What do y’all think?
I think it should just require a permit, like every other solar installation. Unless we can provide data to show that it’s not a problem in existing areas where this is common, and we research and follow their regulations.
Yes but many inspectors and insurance companies won’t want you to install electrical equipment on “real property” or buildings if it isn’t UL as that falls into the scope of AHJs and insurance providers. If there’s something that has the potential to start a fire, you need to have safety certifications so operating the system not only reduces the risk of fire, but also selling the house in the future to a new owner doesn’t come with excess burden on behalf of the next insurer.
If your solar system is off-grid AND off-building, I see no reason that you need to have a UL listed system.
This is of course dependent on local AHJs and utilities, but UL 1741 covers both standalone (off-grid) and grid-interactive (on-grid) inverters. If you’re choosing an inverter manufacturer that makes non-UL listed off-grid inverters, I would probably be suspect of their products’ quality as it’s easier to gain UL listing regardless of how the inverter is used: off-grid or grid-interactive.
That’s the problem.
That is a problem. Off-grid inverters that aren’t certified to UL 1741-SB aren’t required to have anti-islanding protection that cuts the inverters off if there’s an absence of grid voltage. If a “balcony solar” inverter were to NOT cease to energize upon loss of grid and stay islanded, then voltage is introduced to the building’s/community’s shared local distribution system. If work were to be done on that portion of the distribution system or grid where lineman and wireman expect conductors to be de-energized, then you might have injuries as a result. Now, you may be able to say that lineman and wireman should always test for presence of voltage prior to doing work, and as a solar engineer I would absolutely expect folks to do this, but that’s not always the case. People cut corners. And in the event that certain crews cut corners, don’t check for voltage and investigate where the voltage source is, and start touching wires and introducing paths to ground, people can get seriously injured or die.
You may think that because solar panels are current-limited that this fact protects workers in the event of becoming exposed to live voltage, but any combination of voltage and current can kill.
I’ve always wanted DRM for my inverter.
In the context of safety, this is a good thing. Skirting DRM on movies or TVs won’t mean you injure yourself or others or worse. Skirting inverter settings can cause inverters to operate in ways that are unintended, and could hurt people. These things are not the same, and it’s concerning that you can’t see the difference.
Also, having locks on settings means that other bad actors are deterred from changing those settings maliciously, whether intentional or not.
There is not substitute for a qualified person operating and maintaining an electrical system, regardless of voltage.
I know it because it’s in the spec necessary for licensing. It shuts off in under 20 ms so you can’t even get shocked by the prongs of the plug if pulled out.
It is a commercial product, connected to the grid via a standard schuko plug, sold in Germany. It has to be compliant with the local law to be sold legally.
It is a commercial product, connected to the grid via a standard schuko plug, sold in Germany.
Or you buy it in Aliexpress/Temu and it will have whatever it will have, no policeman is going to come check if the panel they see from the street has a stamp or not.
But if your house burns down because of your unlicensed configuration, the insurance won’t pay, and if people got hurt there will be a criminal investigation.
So you can’t buy raw solar panels or inverters in Germany?
Sure you can. Solar panels will be fried by grid voltage more or less immediately if you connect them directly to a wall socket and become useless.
You cannot buy a PV inverter in Germany (entire EU really) that doesn’t automatically shut off if it doesn’t detect a frequency to sync against from it’s AC side, unless it can run off-grid in which case it has to disble the grid connection within the same 20ms.
You cannot buy a PV inverter in Germany (entire EU really) that doesn’t automatically shut off if it doesn’t detect a frequency to sync against from it’s AC side, unless it can run off-grid in which case it has to disble the grid connection within the same 20ms.
So you can’t buy a grid-connected inverter with off-grid capabilities? Because the inverter has no way to tell the difference between the grid being off, and being off-grid.
Oh you can buy off grid inverters (or inverters capable of “island mode”). But they are required to be able to automatically disconnect from grid, even if they are never going to be connected to a grid. You can’t buy solar inverters without this for the exact reason that you can connect them to grid.
Again, it doesn’t matter what inverter you buy, they can’t tell the difference between off grid and grid off. So if it shuts off when it doesn’t detect voltage, then it won’t work off grid. Which makes it sound like you’re saying off-grid inverters are illegal.
You are required to notify your utilities that you’ll be operating a direct plugged small solar PV installation, that’s it. They can’t forbid you from doing this.
The utilities don’t monitor compliance, the manufacturer is.
The certification on the product shows that it’s safe to use in grid-tie. What the fuck are you on about? Are you just being intentionally an obtuse pain in the ass?
By now over 1.2 million people in Germany have registered (and even more have not registered) their legal small scale solar system and are producing their own electricity (mine covers 2/3rds of my total demand).
UL certification is a requirement for an electric or electronic product to be licensed for sale to consumers in the US. This is enforced on US manufacturers of a product and on importers.
Whilst people buying something from AliExpress for personal use and importing it themselves don’t have to obbey such requirements, those importing them or making them for sale in the US do.
The CE mark does the same thing in the EU.
No idea if in the US there are further licensing requirements for things to be connected to the grid that would close the importing for personal use loophole.
UL certification is a requirement for an electric or electronic product to be licensed for sale to consumers in the US.
That is completely incorrect. I own a ton of equipment that is not UL listed.
Further, UL listed equipment is not prevented from backfeeding to the grid, and in fact most of it is intended for precisely that.
No idea if in the US there are further licensing requirements for things to be connected to the grid that would close the importing for personal use loophole.
Utilities must approve power export to the grid, even if you do the physical installation 100% off the books. It’s called “Permission to Operate”, which requires permits and passed inspections. You can’t just unilaterally add shit to the power grid.
Your link doesn’t mention anything about “balcony solar”.
“Application process for rooftop solar and other smaller systems”. If you want to export power to the grid from anything at all, you must go through this process. If you wanted to export power from a hamster on a wheel you must apply for PTO.
Because the whole point is to make solar easier and more affordable?
of course, but not at the cost of safety and grid reliability.
Again, “other small systems” does not mean “balcony solar”. It could just mean ground-mount systems. Everything I’ve found says it’s not required. I challenge you to find the opposite.
Balcony solar is pretty much “plug and play.” Depending on the state/municipality/utility rules, users can install it themselves and don’t have to jump through all the permitting and contractual hoops or pay electricians in order to get it up and running like homeowners who install rooftop solar do
downvotes because your facts are misinterpreted. This entire discussion is about exporting to the grid. All this legislation does is allow you to use balcony solar for yourself; NOT connecting it to the grid. If you want to export to the grid (like to participate in net metering) you still need PTO.
Easy check, grab a voltmeter and do it yourself.
Pull the plug, set voltmeter to AC, and read the voltage across the prongs. If you get anything over the usual float voltage you get from just holding the probes ungrounded, then you have a problem.
The PRODUCT is designed to stop feeding OUT the plug if it doesn’t detect CURRENT from the socket. AC is alternating current so it pulses on and off so the solar system is doing the same. It’s turning on and off quickly and seeing if it gets power back and if it detects no power incoming it shuts off the power from the solar. It’s quite simple and ingenious.
ok I have to believe the guy replying is a shil at this point. Use of approved products is as old as the electric stystem. Its why the electric company does not have to come and inspect everything you have plugged into the grid and does not come out every time you get a new appliance. The standards are with the product as you correctly point out and the state does not allow on compliant products to be sold just like with refrigerators.
I have to believe the guy replying is a shil at this point
A shill for what, exactly? Linemen safety? The horror.
Its why the electric company…does not come out every time you get a new appliance.
That’s because your appliances aren’t backfeeding to the grid. Anything that does requires inspections and permits, to make sure they don’t kill people , or delay getting the power back on, which can kill people.
but the edge case you give has nothing to do with feeding back to the grid given it was already pointed out they auto shut off which regulated by whats allowed to be sold because anyone could put a non legal thing that feeds energy into the grid even if they jury rigged it themself.
exactly. So people could put power into the grid now and the laws would allow it with approved equipment that meet the requirements like auto shutoff whichi legally would certainly be a given. Could something else be plugged in that did not have it. sure. but that would be illegal same as doing it before its allowed. I really don’t understand how you do not understand this.
yup and if you install it wrong it’s you in trouble but you still can buy them and diy without a permit. They should just be regulated so only the certified ones can be sold.
“The utility” has never had a way to prevent you from doing something dangerous with your wiring or with the electricity they send you. The best we’ve managed has been to encourage appliance manufacturers to design their products with safety in mind, through the UL program (which is voluntary). This is why the writer talked to the “vice president of engineering at UL Solutions.”
How do you know? In a typical solar system, you have to have a permit, which requires an inspector to come out and ensure everything is configured correctly and safely. These don’t require any permits, which is great for making them more affordable and accessible, but there’s also no one coming around to make sure that anyone is doing it safely.
Inverters in the US are all listed to UL1741-SB which dictates that they shall cease to energize their AC outputs if they sense an absence of grid voltage.
Now, one thing people are ignoring is that UL1741-SB allows for islanding protection, and the disablement of it. If an inverter has its settings changed such that islanding protection is OFF, then the inverter will keep sending power to the “grid” because it thinks it’s operating on a microgrid that was previously disconnected from the larger grid via a Microgrid Interconnection Device (MID).
The settings these inverters have are user-settable, which means they need to be checked by a qualified person, either a contractor, engineer, or inspector. These settings must also often be checked by the utility you’re interconnecting to before they allow you to energize, so usually all of these parties have eyes on the inverters’ settings and can stop work before energization until things are corrected.
Ultimately I agree with you. If we don’t want to have to need inspections for every solar installation, especially residential ones and especially where plug-and-play solar modules are used, then inverters need to have their settings pre-configured for the grid code in the factory that then cannot be changed by the user or operator in the field. That would be a way to shoe-in this kind of installation.
Hard setting grid codes into inverters prior to shipping to site might be overly conservative though, especially as utilities change their grid codes over time. You need to have a way to update those settings, which could be using a wireless portal hosted by the inverter OEM with credentials made only available to the OEM. Problem with this is that then you shift the burden of configuration to the manufacturer which already has a ton of other UL standards as well as rules and regulations to follow.
What do y’all think?
I agree with everything you said except shoe-in, because it’s shoo-in.
But you articulated (better than I was going to) the number one issue. Power companies need insurance and their insurance will be affected if ordinance permits basically unchecked generators being plugged into the grid. And before anyone says it, you are not allowed to just plug your generator into your house. Does it happen? Yeah, people have been dumb since day one.
But there are transfer switches that allow for this operation in a safe manner, and the easiest way to deal with this is to have them installed by default in new construction, and to provide incentive for upgrading your panel to include one.
No, they are absolutely not. I don’t know where people are getting this idea. Many inverters aren’t even UL listed. There is absolutely no requirement for them to be. If that were the case, off-grid inverters wouldn’t even be allowed to exist. I own several that do not have this capability and are not UL listed.
Not in the case of Utah’s new “balcony solar” laws. That’s the problem.
Oh goodie, I’ve always wanted DRM for my inverter.
I think it should just require a permit, like every other solar installation. Unless we can provide data to show that it’s not a problem in existing areas where this is common, and we research and follow their regulations.
Yes but many inspectors and insurance companies won’t want you to install electrical equipment on “real property” or buildings if it isn’t UL as that falls into the scope of AHJs and insurance providers. If there’s something that has the potential to start a fire, you need to have safety certifications so operating the system not only reduces the risk of fire, but also selling the house in the future to a new owner doesn’t come with excess burden on behalf of the next insurer.
If your solar system is off-grid AND off-building, I see no reason that you need to have a UL listed system.
This is of course dependent on local AHJs and utilities, but UL 1741 covers both standalone (off-grid) and grid-interactive (on-grid) inverters. If you’re choosing an inverter manufacturer that makes non-UL listed off-grid inverters, I would probably be suspect of their products’ quality as it’s easier to gain UL listing regardless of how the inverter is used: off-grid or grid-interactive.
That is a problem. Off-grid inverters that aren’t certified to UL 1741-SB aren’t required to have anti-islanding protection that cuts the inverters off if there’s an absence of grid voltage. If a “balcony solar” inverter were to NOT cease to energize upon loss of grid and stay islanded, then voltage is introduced to the building’s/community’s shared local distribution system. If work were to be done on that portion of the distribution system or grid where lineman and wireman expect conductors to be de-energized, then you might have injuries as a result. Now, you may be able to say that lineman and wireman should always test for presence of voltage prior to doing work, and as a solar engineer I would absolutely expect folks to do this, but that’s not always the case. People cut corners. And in the event that certain crews cut corners, don’t check for voltage and investigate where the voltage source is, and start touching wires and introducing paths to ground, people can get seriously injured or die.
You may think that because solar panels are current-limited that this fact protects workers in the event of becoming exposed to live voltage, but any combination of voltage and current can kill.
In the context of safety, this is a good thing. Skirting DRM on movies or TVs won’t mean you injure yourself or others or worse. Skirting inverter settings can cause inverters to operate in ways that are unintended, and could hurt people. These things are not the same, and it’s concerning that you can’t see the difference.
Also, having locks on settings means that other bad actors are deterred from changing those settings maliciously, whether intentional or not.
There is not substitute for a qualified person operating and maintaining an electrical system, regardless of voltage.
Agreed
…why would anyone care what those people want?
No you don’t.
You’re missing the point. Nothing is stopping anyone from installing off-grid inverters (or any inverter at all) in an on-grid system.
Have you ever looked at “top sellers” on Amazon? Most people do not care about quality, they just buy the cheapest shit possible.
I see the difference, I just don’t care. It’s concerning that you can’t see the potential for exploitation, both from corporations and governments.
I know it because it’s in the spec necessary for licensing. It shuts off in under 20 ms so you can’t even get shocked by the prongs of the plug if pulled out.
What license? Who is coming to verify your license?
It is a commercial product, connected to the grid via a standard schuko plug, sold in Germany. It has to be compliant with the local law to be sold legally.
It all shouldn’t be so difficult to understand.
Or you buy it in Aliexpress/Temu and it will have whatever it will have, no policeman is going to come check if the panel they see from the street has a stamp or not.
But if your house burns down because of your unlicensed configuration, the insurance won’t pay, and if people got hurt there will be a criminal investigation.
And this still results in innocent third parties being hurt
Yes, so people should stick to the legal options. It isn’t hard.
So you can’t buy raw solar panels or inverters in Germany?
It’s not, which is why I’m not sure why you’re struggling.
Sure you can. Solar panels will be fried by grid voltage more or less immediately if you connect them directly to a wall socket and become useless.
You cannot buy a PV inverter in Germany (entire EU really) that doesn’t automatically shut off if it doesn’t detect a frequency to sync against from it’s AC side, unless it can run off-grid in which case it has to disble the grid connection within the same 20ms.
So you can’t buy a grid-connected inverter with off-grid capabilities? Because the inverter has no way to tell the difference between the grid being off, and being off-grid.
Oh you can buy off grid inverters (or inverters capable of “island mode”). But they are required to be able to automatically disconnect from grid, even if they are never going to be connected to a grid. You can’t buy solar inverters without this for the exact reason that you can connect them to grid.
Again, it doesn’t matter what inverter you buy, they can’t tell the difference between off grid and grid off. So if it shuts off when it doesn’t detect voltage, then it won’t work off grid. Which makes it sound like you’re saying off-grid inverters are illegal.
Of course you can buy whatever you like, and whatever is being sold has to be compliant with local legal requirements.
If you buy illegal stuff and cause problems, you will have problems with your insurance and potentially, legal ones.
And that’s all I’m going to say on the matter. HAND.
There’s no way to prevent people from connecting perfectly legal equipment in an illegal manner, where otherwise there would be.
You are only allowed to sell inverters approved by VDE
Again I ask, if there is no permit, how will the utilities know you are in compliance with this law?
You are required to notify your utilities that you’ll be operating a direct plugged small solar PV installation, that’s it. They can’t forbid you from doing this.
The utilities don’t monitor compliance, the manufacturer is.
So it sounds like you’re saying there is no way? And therein lies the problem.
The certification on the product shows that it’s safe to use in grid-tie. What the fuck are you on about? Are you just being intentionally an obtuse pain in the ass?
Yeah, really weird. It seems like they had some kind of agenda or point to make, but they’re going about it a very strange way.
Are you a fucking moron? What’s to stop anyone from installing an uncertified product?
By now over 1.2 million people in Germany have registered (and even more have not registered) their legal small scale solar system and are producing their own electricity (mine covers 2/3rds of my total demand).
If you think that’s a problem, be my guest.
I don’t know if it’s a problem or not. Do you?
In the United States that would be UL Certification.
UL is not a license. It’s a certification. And you forgot the second question.
UL certification is a requirement for an electric or electronic product to be licensed for sale to consumers in the US. This is enforced on US manufacturers of a product and on importers.
Whilst people buying something from AliExpress for personal use and importing it themselves don’t have to obbey such requirements, those importing them or making them for sale in the US do.
The CE mark does the same thing in the EU.
No idea if in the US there are further licensing requirements for things to be connected to the grid that would close the importing for personal use loophole.
That is completely incorrect. I own a ton of equipment that is not UL listed.
Further, UL listed equipment is not prevented from backfeeding to the grid, and in fact most of it is intended for precisely that.
There aren’t.
You are correct.
A little digging shows that unlike the CE mark in the EU for electronics, “UL certification isn’t mandatory, but may be required when selling electronic items to retailers”.
Utilities must approve power export to the grid, even if you do the physical installation 100% off the books. It’s called “Permission to Operate”, which requires permits and passed inspections. You can’t just unilaterally add shit to the power grid.
https://www.energysage.com/solar/solar-interconnection-what-you-need-to-know/
According to my research, there is no such permit required in Utah. And presumably new legislation is looking to have this exception as well.
not true, you still need to apply to the utility to export to the grid.
https://www.rockymountainpower.net/savings-energy-choices/customer-generation.html
why “presumably”?
Your link doesn’t mention anything about “balcony solar”. And these systems are not supposed to export to the grid anyway.
Because the whole point is to make solar easier and more affordable?
“Application process for rooftop solar and other smaller systems”. If you want to export power to the grid from anything at all, you must go through this process. If you wanted to export power from a hamster on a wheel you must apply for PTO.
of course, but not at the cost of safety and grid reliability.
Again, “other small systems” does not mean “balcony solar”. It could just mean ground-mount systems. Everything I’ve found says it’s not required. I challenge you to find the opposite.
https://cechouston.org/2025/10/21/balcony-solar-something-new-under-the-sun/
E: downboats for facts, I guess
downvotes because your facts are misinterpreted. This entire discussion is about exporting to the grid. All this legislation does is allow you to use balcony solar for yourself; NOT connecting it to the grid. If you want to export to the grid (like to participate in net metering) you still need PTO.
You’re literally the only person talking about exporting to the grid. This discussion is about preventing exporting to the grid.
Downvote because you can be right and also be an asshole.
What part of that did you interpret as me being an asshole?
Easy check, grab a voltmeter and do it yourself.
Pull the plug, set voltmeter to AC, and read the voltage across the prongs. If you get anything over the usual float voltage you get from just holding the probes ungrounded, then you have a problem.
By “you” I did not mean your personal solar system. I mean how does the utility know that other users that have systems connected are doing so safely?
The PRODUCT is designed to stop feeding OUT the plug if it doesn’t detect CURRENT from the socket. AC is alternating current so it pulses on and off so the solar system is doing the same. It’s turning on and off quickly and seeing if it gets power back and if it detects no power incoming it shuts off the power from the solar. It’s quite simple and ingenious.
ok I have to believe the guy replying is a shil at this point. Use of approved products is as old as the electric stystem. Its why the electric company does not have to come and inspect everything you have plugged into the grid and does not come out every time you get a new appliance. The standards are with the product as you correctly point out and the state does not allow on compliant products to be sold just like with refrigerators.
A shill for what, exactly? Linemen safety? The horror.
That’s because your appliances aren’t backfeeding to the grid. Anything that does requires inspections and permits, to make sure they don’t kill people , or delay getting the power back on, which can kill people.
but the edge case you give has nothing to do with feeding back to the grid given it was already pointed out they auto shut off which regulated by whats allowed to be sold because anyone could put a non legal thing that feeds energy into the grid even if they jury rigged it themself.
And I already pointed out that that’s not a given.
And I already pointed out that that’s not correct. In fact most equipment that’s sold does not do that.
Yes, people can do all kinds of things that are illegal. That doesn’t mean we stop trying to prevent it.
exactly. So people could put power into the grid now and the laws would allow it with approved equipment that meet the requirements like auto shutoff whichi legally would certainly be a given. Could something else be plugged in that did not have it. sure. but that would be illegal same as doing it before its allowed. I really don’t understand how you do not understand this.
I am not asking how the technology works. I am asking how the utility verifies that people are using compliant products.
The same way they do now.
You realize generators exist right?
Permanently connected generators typically require permits.
yup and if you install it wrong it’s you in trouble but you still can buy them and diy without a permit. They should just be regulated so only the certified ones can be sold.
No, it’s the linemen who are in trouble.
So you want to ban the sale of raw solar panels and inverters?
I can go to the store today and get a generator and plug it right into my house and backfeed.
I know this is idiodic so I don’t do it.
It’s not just idiotic, it’s illegal, and you’ll face repercussions.
“The utility” has never had a way to prevent you from doing something dangerous with your wiring or with the electricity they send you. The best we’ve managed has been to encourage appliance manufacturers to design their products with safety in mind, through the UL program (which is voluntary). This is why the writer talked to the “vice president of engineering at UL Solutions.”
Yes they have. It’s called permitting.
And what’s stopping you from doing it anyway?
If you’re gonna break the law, you’re gonna break the law and we can just ignore any discussion of legality. But that’s not what we’re doing.