The_Sun1d ago
CurlyParakeet 🇪🇺🏳️‍🌈🇺🇦

I have a question about plug in solar panels 🙋‍♀️

Looking the ones available in Europe, the idea seems to be solar panels -> micro inverter-> plug into wall.

I feel like I’m missing something fundamental about household circuits. Why / how does plugging a power source into a normal plug socket work? And second question, would it work the same in the UK?

#solar #fediAsk #question

Mar 27 at 1:53pmWeb
Show threadSven1d ago

@CurlyParakeet the inverters only supply power if they recognize they are connected to the grid and need to turn off immediately if disconnected (so if you unplug it there is no power on the plug and its safe to touch) and the power limit is chosen so legally compliant wiring won't be overloaded by accident.

And then a lot of standardization process to create the rules making this actually legal.

Show threadKeith1d ago
@CurlyParakeet It sends electricity through your ring main and your appliances use that before they start drawing from the grid apparently. My question is, if this is possible, which it seems to be, then why only now?
Show threadSeanBurlington 🌈 🕊️1d ago

@keefeglise @CurlyParakeet

Either "for safety reasons" or "because of industry lobbying" depending what you believe

Show threadKeith1d ago
@sean @CurlyParakeet I'm probably more comfortable with if it's the latter!
Show threadChloé Raccoon1d ago
@keefeglise @sean @CurlyParakeet @PetraPhoenix Also limitations: I have a 5.1kW array connected to a 3.85kW inverter.
A socket can handle 3.1kW.
Show threadSeanBurlington 🌈 🕊️1d ago

@chloeraccoon @keefeglise @CurlyParakeet @PetraPhoenix

I think the original post was UK specific

the UK limit for plug in will be 800W according to this

https://www.britishgas.co.uk/the-source/news/plug-in-solar-panels-explained.html#q1

Plug In Solar Panels Explained: What UK Households Need to Know

Plug in solar panels could be on sale in the UK within months. Learn how they work, new safety rules, potential savings and what the Government’s changes mean for homes.

Show threadChloé Raccoon1d ago
@sean @keefeglise @CurlyParakeet @PetraPhoenix Sorry, I guess I should move out of the UK and not say anything then.
Show threadCurlyParakeet 🇪🇺🏳️‍🌈🇺🇦1d ago

@chloeraccoon

That’s much more than I expected!

Show threadChloé Raccoon1d ago

@CurlyParakeet BS1363 (ie: the UK socket/plug) is rated to run at 240V@13A, which is 3120W/3.1kW.
It's _safety_ rating is 250V@15A, or 3750watts/3.7kW.
So even in "normal" use, it can carry a lot of power, and there's still quite a large safety margin built in.

So for a smaller array, there is no different electrically from an array/inverter being wired in or plugged in.
That mine goes in via it's own breaker into the distribution board is more a requirement of how high the peak power is.
Now, legal allowances of what you are allowed to do may be different to the electrical spec!

Show threadChloé Raccoon1d ago

@CurlyParakeet @PetraPhoenix There's no difference between plugging in an inverter and having one wired in, except for the socket.

The way they work is the same, it's just a device that monitors the input (to sync to it, and for safety) and then injects electricity into the system.
Other devices don't care where the power is coming from, just that it's there. So inverter/battery/mains, it's just electricity to the devices using it.

The safety part the same for both systems, but for more reasons for a plugin unit.
As someone else said, the device monitors the grid feed to make sure when you unplug it (and so it can't "see" the grid) it turns off it's output so you don't get a shock or worse.

Show threadChloé Raccoon1d ago
@CurlyParakeet @PetraPhoenix
The other side of this (which wired in inverters do too) is a direct feed inverter (ie: designed not to operate with out the grid) use that feed in from the grid to a) sync up their sine wave to the gird, because if your system is say, 1Hz off the gird, this is Bad(TM).
And b) so if the grid fails, you don't back feed it and kill the poor tech down the line fixing it!
Show threadCurlyParakeet 🇪🇺🏳️‍🌈🇺🇦1d ago

@chloeraccoon

Thank you for your reply!

I think it answers my question(s). I think maybe I was struggling with the “yes, it’s that simple” part. It almost feels like there should be more to it!

@PetraPhoenix

Show threaddonburi11h ago
@CurlyParakeet @chloeraccoon @PetraPhoenix One other point: for safety, it needs to be on it's own breaker. No possible loads on the same circuit. That stops an idiot plugging in five of them plus five three-bar fires and the washing machine, and overloading the wires embedded in the wall.
Show threadChloé Raccoon11h ago

@donburi @CurlyParakeet @PetraPhoenix Hard wiring also makes isolation easier to wire in, given the size of most isolation switches!
To give you an idea, due to the location of my inverter with regard to the distribution board, the cabling/switches goes:
Distboard breaker -> isolation switch -> cabling -> isolation switch -> inverter (then DC isolation switch on the panel side).

Sometimes you just need the space to fit it all ;)