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#1846540
I've got a very large 3 phase solar panel setup in the field next to the house. Its a bit of a mish-mash of old and new, the new bit being a 3-phase 30kw inverter. The sunny days recently it's been running at close to 100%. Here's the screen:
Image

Now - the problem. Onto the terminals for this, I've attached a thin rubber cable and a socket - just to run a little camera. Should all work I think... but apparently it has other ideas. When I connect the 12v 1.5a power adapter (18 watts) it causes a massive voltage drop on phase-1 causing the inverter to turn off. Voltage goes from 248v down to 123v. I don't get it! surely the voltage drop would just be to the device at the end of the thin wire.

I am puzzled - can anyone explain the physics and what on earth could be wrong?
Image

One more detail - I have another little socket at the mid point - the 'outdoor junction' also on L1+N and the power adapter works fine there.
#1846616
@carlmeek please tell me you have a circuit breaker between the inverter and the 0.75 flex?

Assuming you've double checked your wiring, have you tried plugging anything else in the socket?
#1846622
Yes, and yes. A little MCB at 6 amps. (smallest I had).
Wiring is spot on, and 240v is tested at the little socket.
I haven't tried plugging anything else in yet- I'll do that as soon as it stops raining :-)
#1846648
Some inverters will throttle their output based on frequency shifts downstream - it's how the Tesla powerwall gets an inverter to reduce output when batteries are full. Could be your camera power supply is initiating a shift, confusing the inverter.
#1846651
My diagram is a bit Carp - but wiring all the way from the meter to the inverter is 3 phases + Neutral + Earth. Earth is spiked in multiple locations. It's a TT system.

My socket is just wired into the cable at the inverter end into L1+N+E. It tests as 248v, and appears fine until you plug the adapter in.
#1846673
carlmeek wrote: I've attached a thin rubber cable and a socket - just to run a little camera.

There's your problem, copper or ali works much better :D

Does sound like you've wired up the socket wrong and you are causing a short.
Get one of these, I've got one from Aldi/Lidl:
https://www.screwfix.com/c/tools/electr ... cat7910008
Last edited by Boxkite on Thu May 13, 2021 10:28 am, edited 1 time in total.
#1846679
Is the inverter designed to let you draw power between one phase and your "neutral"? If not, maybe it's sensing that as a fault, instead expecting you to draw power between two phases* directly instead?

* note: higher voltage expected if you do that!
#1846693
rdfb wrote:Is the inverter designed to let you draw power between one phase and your "neutral"? If not, maybe it's sensing that as a fault, instead expecting you to draw power between two phases* directly instead?

* note: higher voltage expected if you do that!



Yes - i'm thinking that too, that it thinks there is a fault. If this were a direct connection to the grid 3 phase supply that you are feeding into then the point that you connect to one phase would be identical to connecting to one phase of the grid (and you havent because my lights didnt go dim :D ) .

So i'm not sure exactly where you are tapping into the Grid/Invertor?
#1846832
Well - I fixed it.

The armoured cable going in is rather rigid, and it had pulled the Neutral lead out of the inverter. So the inverter clearly doesn't need a neutral, it was happy chugging away at 100% with 3 phases. Meanwhile, the N was connected to my little socket, and clearly not being connected at the inverter end caused total havoc!
Sooty25 liked this