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"Plug-In" solar system?
Hey everyone,

some days ago my neighbour told me about his new project and showed my this website: (i hope i dont hurt any rules by this.. i just want you to know what im talking about)
(website is in german):

As far as my neighbour told me this system is meant to be integrated anywhere in the house. So you can connect it anywhere in the house to your existing electric installion without any further special installation to the main grid connection.

After a short google search this really seems to be a thing but i have some serious concerns about this:

1. What if i want to work on my electric installation in my kitchen? so I pull the breaker for the kitchen and I start to work and suddenly boom => I get shocked because maybe there is still power from the solar system. And the worst thing these system dont even have a breaker so this could get really serious right?

2. what if my electric company has to work on the main grid and turns down the electricity in the whole street. Couldnt it happen that i backfeed the main grid without them knowing and the worker gets shocked?

3. what if my solar system produces more energy than my whole house needs so i feed back into the system and give it to my neighbors who have to pay for this since its running over their counter?

4. if 3. happens - does my counter count backward if i backfeed into system?

What do you think am i totaly wrong? do i miss something here?
All your questions have been answered by typical proper "grid-tie" systems.
Q1 & Q2: If normal mains is lost, the solar gear should sense this with "anti-islanding" technology & shut down as well.

Q3 & Q4: That's what normally happens if your system "net exports" back to the grid.
Your neighbour wouldn't pay any more than "normal", the grid just soaks it up. Them being a consumer, yes you might be helping power your neighbors place.
Yes your old analogue meter might count backwards, but modern electronic meters don't unless configured to, & you'd need to talk to your power company pretty soon.
They won't like "non-grid-tie rule compliant" systems....
Running off solar, DIY & electronics fan :-)
Those "plug in" inverters are illegal in most areas. In addition to lineman safety, they pose a huge fire risk because your circuit is being fed from two ends now, the receptacles and the breaker panel, allowing more current to be delivered to any receptacles along the way. I suppose if the receptacle you're plugging it in to is a dedicated circuit, that part isn't relevant, but it's still illegal in most areas...
Korishan likes this post
As Mike said. Also note that those "plug and pray" systems doesnt save you from not having a permit Wink

For instance in Sweden if you back feed to the grid you actually have to pay for it if you dont have the correct meter. And you can expect a nice fine for it unless you have a permit!
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These "plug & play" solar panels with microinverters (also called "Balkonkraftwerke") are pretty save concening electrical shocks. They depend on existing grid power won't supply power if there's no grid power on the line. You could even touch the plug terminators with full sunlight on the panels - nothing will happen. But there's a risk of feeding back to the grid when you produce more power than you consume in your household. That's why those devices usually are configured to produce less than you need. But as far as I know, they must be somehow registered with the power company, because there could be a power backfeed any time...

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(02-12-2019, 09:23 AM)owitte Wrote: These "plug & play" solar panels with microinverters (also called "Balkonkraftwerke") are pretty save concening electrical shocks. They depend on existing grid power won't supply power if there's no grid power on the line. You could even touch the plug terminators with full sunlight on the panels - nothing will happen.

You missed the risk of feeding a branch circuit from both ends, thus the possibility of delivering more current than the breaker can handle.


In the diagram above, the inverter is plugged in to #3. All outlets 1, 2, and 4 can be fed from both the breaker panel and the inverter. The outlets can now supply 15A from the panel and whatever the inverter is putting in. Very dangerous considering the breaker is usually sized to the wiring and receptacles used.

I cannot speak for other areas of the world, but do not use these in the United States.
Korishan and Geek like this post
okay so i had a short phone call with the main grid guy.
he told me here in austria you are allowed to install up to 600wp without the need of any special permission.
but the system has to have a special plug (so you cant connect it the wrong way i guess) and this system has this special plug.

so yeah for a small solar system it seems to be no problem and maybe i will go for it to get things started...
In the long run i will go for a professional solar system for sure.

oh another question about this:

lets say i go for this system and there is also a device which counts the output of my solar...
there is no way to tell where the electric power went right? but i could be sure to use all the power myself because it will allway search for the leat resistance. Or could it happen that my neihgbor gets my electricity even when i could need it myself?
No, the power always takes the shortest route. So as long as you consume more than you generate, no power will leave your circuit. Its however hard to ensure that if you go over a couple of hundred Watts of generator power. That's why I ended up here and built a second life battery.

Edit: In Germany (and in Austria too afaik) we typically have a 3 phased grid. This can lead to a situation where the phase your inverter is on feeds back energy to the grid whereas some of your appliances use grid energy on a different phase. Mechanical counters will summarize over all phases and therefore net this out, but electronical counters might not.

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