I mean, it makes sense to me that consumers can’t be pumping energy into the grid with no way to cut it off, but I’m not a lineman or some sort of civil engineer or whatever.
But if I were a lawmaker, I’d be on the phone with the Germans, who have 1.2M of these connected, and figuring out if and how they’re doing it safely. But lawmakers seem to be somehow incapable of reaching out to people who know fuck all about anything.
I had a chat about this with a friend who works for the national grid (UK).
Apparently the problem is keeping the grid balanced and stable. Basically, the grid struggles to react fast, so they plan ahead. Things like large scale solar can provide predictions on output. Home solar can’t.
When clouds pass over an area it can cause slumps and surges in the local grid. The more home solar, the worse it gets. The current grid is designed to work top down, with predictable changes in demand. It needs upgrading to deal with large scale bidirectional flows.
The plug in units are (potentially) even more ropey. If used properly, they are no worse than normal home solar. Unfortunately, being cheaper, there are worries over the microinverters not shutting down. Either due to the manufacturer cheaping out, or turning on an “off grid” mode.
There are also worries about overloading household circuits. Back feeding bypasses the household circuit breakers and RCDs. They could overload wall wiring and cause fires, or stop an RCD tripping, allowing for a person to be shocked.
I don’t know how much this would apply to the American Grid, but I would imagine it would be worse. Your grid is older and larger. You also use 120VAC which makes the current overload issue a lot worse.
You also use 120VAC which makes the current overload issue a lot worse.
Voltage inside of residences is 120v AC, but its 240v thats delivered to each house. I think a bigger difference is that in the USA that 240v AC is single phase where I believe (Germany included) many nations in the EU are 3 phase.
The USA does have 3 phase power for most commercial applications though.
Hmmm, I wonder how this would affect things in the future where this is widely used.
I.E. if you had both widespread solar usage and some kind of large blackout, would it be hard to get all your solar back online because it’s all in the “waiting for the grid” state? And the grid can’t come back at capacity because all the solar it’s expecting is out?
I assume people smarter than me have this figured out, but just a random thought if anyone knows more.
What happens when someone makes an unsafe backfeed into a downed grid and then other nearby inverters detect the current and bring themselves back online? Is there a way to detect if the load is being delivered from the utility vs from incorrectly configured solar or generator installations?
Some others are arguing back and forth about this elsewhere in the thread and I see the reasoning: unpermitted systems could accidentally energize isolated portions of the grid during downtime, which might trick properly installed systems to also come back online, and you have a runaway effect where there is enough current present to allow addition safety systems to be fooled.
There isn’t any data transmission over the wires; there either is current, or there isn’t. Arguing over permitting is moot - either safety systems can handle this scenario already, or they can’t.
All paperwork does is slow the relief of dependence on the utility, which hurts their profits.
The same thing that currently happens when somebody does that with a gas generator? Linepersons get zapped… people get sued… etc…
There isn’t any data transmission over the wires…
That’s very wrong. Not only can you extend Ethernet in your own home using your power outlets, the power companies have been reading meters this way for decades.
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.
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.
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.
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.
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
These systems are designed to not push power back up if the grid goes down. In most areas, the municipality won’t even allow a solar installation to be connected or even finished without it being inspected to verify you have that sort of setup.
The article clearly mentions California, Utah, Arizona, New Mexico, Washington and Wyoming. Perhaps others that I missed as well. Your comment I replied to was not specific to a location, you said “it makes sense to me that consumers can’t be pumping energy into the grid with no way to cut it off” and I was letting you know that it shouldn’t be a concern because that isn’t how solar power systems work. Do you think that Utah will work different for some reason?
The article clearly mentions California, Utah, Arizona, New Mexico, Washington and Wyoming.
Those are potential future locations, not current ones. Any discussion around them would be purely hypothetical. I am discussing reality.
that isn’t how solar power systems work.
Solar systems can work in any number of ways. That’s why we have regulation, to ensure they do work in specific ways. Utah currently has no such regulation. It’s “plug and play”. People literally just buy them, hang them up, and plug them in.
In the US, reaching out to other countries for advice, even if they’re our allies, seems to be viewed as treason. At a minimum, seems like treason against “real” masculinity, on which American culture is fueled, especially now.
Sure, but the article specifically mentions Germany, which leads me to believe they’re likely most abundant in that region?
Pretty sure there are tons of people who would be willing to advise on how to improve the world without discussion of tariffs that are entirely in the control of a single moron-in-chief.
Germany has a lot of plug-in solar for balconies (Balkonkraftwerke) and it’s available at very cheap prices (example here). I know it only provides up to 800W on a very sunny day but that’s still a significant amount for an apartment. And the beauty of these is that they are so plug-and-play, everything is included. You hang it, connect the cables and plug it into a socket and then you’re done.
I live in the Netherlands but I’ve been seriously considering picking up one of these if my building HoA doesn’t want to do a rooftop solar project for our building.
I wasn’t aware balcony solar isn’t a thing in other countries because it’s everywhere here in Germany. So I was wondering what new thing they are talking about being even more easier.
It is more than just the concern around back-feeding the grid. These simple balcony setups connect to your home grid via a single outlet. Most US outlets/circuits are 15 AMP or roughly 1500 watts max capacity. These single circuits can only carry that much current total at any one time so if you have it loaded up with incoming power AND use anything else on the circuit at the same time … no bueno. To make this setup work best/safely you would ideally want a dedicated circuit for it which is basically non-existent today.
The safety issues really do need to be addressed because the folks most likely to use these systems are apartment dwellers and I don’t think anyone wants to increase fire risk in these scenarios.
His point was that if you’ve got 1200w incoming from the panel then you only have 300w of overhead on that circuit before the circuit breaker blows.
Sure, it’s within the limit on its own, but without a dedicated circuit for it you’ll be blowing a fuse pretty frequently when trying to use nearby plugs and lights.
Idk man. It’s probably over my head but I still don’t think the wires themselves could take it. In my thought process you’ve got more electricity flowing around on the circuit and even if it gets used before getting to the breaker things are going to be heating up pretty quick.
To me it sounds like trying to hook up a power plant to a data center via an indoor extension cord. It’s gonna melt.
I think the warning you might be thinking of is that a breaker can fail to pop if an inverter/generator is on the same circuit as a high wattage device. Since some energy would go directly from generation to device, the breaker will only see the “net” energy consumption. So if the generator puts out 1500W and the device decides to draw 3000W, a 15A breaker only sees 1500, and won’t trip even though the device is pulling way too much. If the breaker was sized for the wiring, then the wiring to that outlet could catch fire due to the breaker not tripping. That’s the main reason I know of why a generator or inverter should be on a dedicated circuit, to force the energy out one breaker and in another, so that the breaker can see an accurate measure of energy and trip when necessary.
even if it gets used before getting to the breaker
It would be both added and consumed after the breaker. Like if you had a 10A solar system connected to a dual outlet, and a 10A space heater on the other outlet, there would only be 10A flowing through the outlet, and nowhere else in the system
Yes, I was conceding that point. I was then worried about the actual romex in the walls entirely contained after the breaker. Are you able to pump as much power as you want at 15A on a 15A rated wire? There’s got to be some limit, right?
I think the risk is more that someone has a 15A-rated outlet on a 15A circuit breaker, plugs a solar panel into one socket and then a power strip with 30A of space heaters into the other socket. Breaker doesn’t trip because the main panel is only providing 15A, but the outlet lights on fire.
Not sure why that isn’t a problem in places these are more common.
This is not it. Not only is there a microinverter and a breaker there to address that issue, but my understanding as a layman is the load in the circuit is down to how much you’re drawing (i.e. if you’re generating 1200 behind the microinverter and pulling 1500 you’re pulling 1500 through the circuit, not 2700).
The bigger fire hazard here is the battery many of these come with for storage, honestly.
That’s not to say there isn’t a bit of a risk. You need to be careful if you need to do something in the installation that you disable both the grid breaker and the microinverter. Otherwise it’s entirely possible for the grid safety to blow and the inverter to keep pumping power into your house. But as the previous poster says, there’s a reason these are legal to install in apartments all over Europe, and it’s not just European grids being set for higher amps. FWIW, most of these kits come with 800W max out. My understanding is they’re perfectly fine to use as a cost mitigation and they’ll keep your fridge going in a blackout but no, they won’t be constantly tripping your fuse.
There are a lot of circuits in the US that power multiple duplex outlets around a room. You could plug in a solar panel into one outlet and a load into another and they would be connected by a length of Romex in the walls.
Generally that’s fine and I agree, but one edge case that people overlook that I think is worth mentioning (and maybe what gp heard about and is trying to articulate) is that having an inverter or generator on the same circuit as a big energy consumer means that the breaker wouldn’t see the total energy being used by the consumer, and so it might not trip even if the consumer pulls too much wattage. That’s the main reason I know of why power sources should be on their own breaker - so it doesn’t hide power from the breaker but forces it to go out the generator circuit breaker and back in the consumer breaker so it can be protected properly.
I mean, it makes sense to me that consumers can’t be pumping energy into the grid with no way to cut it off, but I’m not a lineman or some sort of civil engineer or whatever.
But if I were a lawmaker, I’d be on the phone with the Germans, who have 1.2M of these connected, and figuring out if and how they’re doing it safely. But lawmakers seem to be somehow incapable of reaching out to people who know fuck all about anything.
I had a chat about this with a friend who works for the national grid (UK).
Apparently the problem is keeping the grid balanced and stable. Basically, the grid struggles to react fast, so they plan ahead. Things like large scale solar can provide predictions on output. Home solar can’t.
When clouds pass over an area it can cause slumps and surges in the local grid. The more home solar, the worse it gets. The current grid is designed to work top down, with predictable changes in demand. It needs upgrading to deal with large scale bidirectional flows.
The plug in units are (potentially) even more ropey. If used properly, they are no worse than normal home solar. Unfortunately, being cheaper, there are worries over the microinverters not shutting down. Either due to the manufacturer cheaping out, or turning on an “off grid” mode.
There are also worries about overloading household circuits. Back feeding bypasses the household circuit breakers and RCDs. They could overload wall wiring and cause fires, or stop an RCD tripping, allowing for a person to be shocked.
I don’t know how much this would apply to the American Grid, but I would imagine it would be worse. Your grid is older and larger. You also use 120VAC which makes the current overload issue a lot worse.
Voltage inside of residences is 120v AC, but its 240v thats delivered to each house. I think a bigger difference is that in the USA that 240v AC is single phase where I believe (Germany included) many nations in the EU are 3 phase.
The USA does have 3 phase power for most commercial applications though.
The microinverters stop feeding in if grid goes down. So it’s safe.
Hmmm, I wonder how this would affect things in the future where this is widely used.
I.E. if you had both widespread solar usage and some kind of large blackout, would it be hard to get all your solar back online because it’s all in the “waiting for the grid” state? And the grid can’t come back at capacity because all the solar it’s expecting is out?
I assume people smarter than me have this figured out, but just a random thought if anyone knows more.
What happens when someone makes an unsafe backfeed into a downed grid and then other nearby inverters detect the current and bring themselves back online? Is there a way to detect if the load is being delivered from the utility vs from incorrectly configured solar or generator installations?
Some others are arguing back and forth about this elsewhere in the thread and I see the reasoning: unpermitted systems could accidentally energize isolated portions of the grid during downtime, which might trick properly installed systems to also come back online, and you have a runaway effect where there is enough current present to allow addition safety systems to be fooled.
There isn’t any data transmission over the wires; there either is current, or there isn’t. Arguing over permitting is moot - either safety systems can handle this scenario already, or they can’t.
All paperwork does is slow the relief of dependence on the utility, which hurts their profits.
The same thing that currently happens when somebody does that with a gas generator? Linepersons get zapped… people get sued… etc…
That’s very wrong. Not only can you extend Ethernet in your own home using your power outlets, the power companies have been reading meters this way for decades.
Kinda seems like something you might want to avoid…
Obviously. I was just pointing out that it isn’t an issue unique to solar.
It is unique to “balcony solar”. Typical solar systems require permits and inspections before connecting.
No it isn’t. The same thing happens with the kind of gas generators you can get from your local hardware store all the time.
As I mentioned several times elsewhere, gas generators also typically require permitting.
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.
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.
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.
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.
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.
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
These systems are designed to not push power back up if the grid goes down. In most areas, the municipality won’t even allow a solar installation to be connected or even finished without it being inspected to verify you have that sort of setup.
What system?
My research shows theres no permitting required in Utah but please correct me if I’m wrong.
Did you respond to the wrong message? Nothing I said anything to do with Utah.
Did you respond to the wrong thread? Because the OP is about Utah.
The article clearly mentions California, Utah, Arizona, New Mexico, Washington and Wyoming. Perhaps others that I missed as well. Your comment I replied to was not specific to a location, you said “it makes sense to me that consumers can’t be pumping energy into the grid with no way to cut it off” and I was letting you know that it shouldn’t be a concern because that isn’t how solar power systems work. Do you think that Utah will work different for some reason?
Those are potential future locations, not current ones. Any discussion around them would be purely hypothetical. I am discussing reality.
Solar systems can work in any number of ways. That’s why we have regulation, to ensure they do work in specific ways. Utah currently has no such regulation. It’s “plug and play”. People literally just buy them, hang them up, and plug them in.
In the US, reaching out to other countries for advice, even if they’re our allies, seems to be viewed as treason. At a minimum, seems like treason against “real” masculinity, on which American culture is fueled, especially now.
‘Why don’t you just stop to ask for directions?’
‘I know where I’m going!!1!1111!1!!!1!’
🙄
They are commonly used in many parts of Europe.
If you drop some Tariff percentages, we might be willing to advise.
Sure, but the article specifically mentions Germany, which leads me to believe they’re likely most abundant in that region?
Pretty sure there are tons of people who would be willing to advise on how to improve the world without discussion of tariffs that are entirely in the control of a single moron-in-chief.
Germany has a lot of plug-in solar for balconies (Balkonkraftwerke) and it’s available at very cheap prices (example here). I know it only provides up to 800W on a very sunny day but that’s still a significant amount for an apartment. And the beauty of these is that they are so plug-and-play, everything is included. You hang it, connect the cables and plug it into a socket and then you’re done.
I live in the Netherlands but I’ve been seriously considering picking up one of these if my building HoA doesn’t want to do a rooftop solar project for our building.
Yes, that was mentioned in the OP as well as the comment you replied to.
I wasn’t aware balcony solar isn’t a thing in other countries because it’s everywhere here in Germany. So I was wondering what new thing they are talking about being even more easier.
It is more than just the concern around back-feeding the grid. These simple balcony setups connect to your home grid via a single outlet. Most US outlets/circuits are 15 AMP or roughly 1500 watts max capacity. These single circuits can only carry that much current total at any one time so if you have it loaded up with incoming power AND use anything else on the circuit at the same time … no bueno. To make this setup work best/safely you would ideally want a dedicated circuit for it which is basically non-existent today.
The safety issues really do need to be addressed because the folks most likely to use these systems are apartment dwellers and I don’t think anyone wants to increase fire risk in these scenarios.
That’s why they’re limited to 1200 watts.
His point was that if you’ve got 1200w incoming from the panel then you only have 300w of overhead on that circuit before the circuit breaker blows.
Sure, it’s within the limit on its own, but without a dedicated circuit for it you’ll be blowing a fuse pretty frequently when trying to use nearby plugs and lights.
As I said, that’s not how that works. You can have 10A incoming and 10A outgoing and the circuit load is still 10A.
Idk man. It’s probably over my head but I still don’t think the wires themselves could take it. In my thought process you’ve got more electricity flowing around on the circuit and even if it gets used before getting to the breaker things are going to be heating up pretty quick.
To me it sounds like trying to hook up a power plant to a data center via an indoor extension cord. It’s gonna melt.
I think the warning you might be thinking of is that a breaker can fail to pop if an inverter/generator is on the same circuit as a high wattage device. Since some energy would go directly from generation to device, the breaker will only see the “net” energy consumption. So if the generator puts out 1500W and the device decides to draw 3000W, a 15A breaker only sees 1500, and won’t trip even though the device is pulling way too much. If the breaker was sized for the wiring, then the wiring to that outlet could catch fire due to the breaker not tripping. That’s the main reason I know of why a generator or inverter should be on a dedicated circuit, to force the energy out one breaker and in another, so that the breaker can see an accurate measure of energy and trip when necessary.
I do know, man.
It would be both added and consumed after the breaker. Like if you had a 10A solar system connected to a dual outlet, and a 10A space heater on the other outlet, there would only be 10A flowing through the outlet, and nowhere else in the system
Yes, I was conceding that point. I was then worried about the actual romex in the walls entirely contained after the breaker. Are you able to pump as much power as you want at 15A on a 15A rated wire? There’s got to be some limit, right?
No. You can only pump 15A. But you’ll never have more than that.
1200 incoming + 1 hairdryer at the same time equals overloaded circuit though.
That’s now how that works. You got 1200 coming in and 1200 going out, so the solar would just power the dryer directly.
I think the risk is more that someone has a 15A-rated outlet on a 15A circuit breaker, plugs a solar panel into one socket and then a power strip with 30A of space heaters into the other socket. Breaker doesn’t trip because the main panel is only providing 15A, but the outlet lights on fire.
Not sure why that isn’t a problem in places these are more common.
(this is the same reason that big solar systems require an oversized busbar on your main panel)
Ah, that is a good point. I wonder how they’re mitigating that.
breaker masking
This is not it. Not only is there a microinverter and a breaker there to address that issue, but my understanding as a layman is the load in the circuit is down to how much you’re drawing (i.e. if you’re generating 1200 behind the microinverter and pulling 1500 you’re pulling 1500 through the circuit, not 2700).
The bigger fire hazard here is the battery many of these come with for storage, honestly.
That’s not to say there isn’t a bit of a risk. You need to be careful if you need to do something in the installation that you disable both the grid breaker and the microinverter. Otherwise it’s entirely possible for the grid safety to blow and the inverter to keep pumping power into your house. But as the previous poster says, there’s a reason these are legal to install in apartments all over Europe, and it’s not just European grids being set for higher amps. FWIW, most of these kits come with 800W max out. My understanding is they’re perfectly fine to use as a cost mitigation and they’ll keep your fridge going in a blackout but no, they won’t be constantly tripping your fuse.
If you use anything else on the circuit the power from the solar will just go directly into that device and bypass the wall wiring entirely.
There are a lot of circuits in the US that power multiple duplex outlets around a room. You could plug in a solar panel into one outlet and a load into another and they would be connected by a length of Romex in the walls.
Generally that’s fine and I agree, but one edge case that people overlook that I think is worth mentioning (and maybe what gp heard about and is trying to articulate) is that having an inverter or generator on the same circuit as a big energy consumer means that the breaker wouldn’t see the total energy being used by the consumer, and so it might not trip even if the consumer pulls too much wattage. That’s the main reason I know of why power sources should be on their own breaker - so it doesn’t hide power from the breaker but forces it to go out the generator circuit breaker and back in the consumer breaker so it can be protected properly.
This is why balkonkraftwerk is limited to 800 W feed-in.
They have been constantly working to reach out to the utility companies to find a way to halt this.