LED lights on multiple circuits suddenly started ghosting when running off grid on batteries

nimrod86

Friend is messaging me with a strange one here: he's had no power at home since last Friday and has been running off batteries and solar with a changeover switch since then. Tonight, out of nowhere the LED lights in his kitchen, and the floodlights outside on the shed started ghosting (faintly glowing). Nothing has changed in the past week at all, in fact the power line to his house is currently in two halves up the road!

The lights are off at the switch, and he's knocked off the MCB for the lighting circuit, but glow persists. Putting the changeover switch to the middle position (neither grid or battery), or Grid kills everything and the glow stops as expected. Put it back to battery and it starts.

Anything we can google talks about capacitive coupling on circuits but these all seem to be about newly replaced lights or new builds. This has only started happening tonight, and wasn't happening for the past week on batteries, or years on grid before. I did tell him to knock off the lights first, then one by one knock off the rest of the MCB's for all other circuits to see if something else is affecting it. He turned everything off at the consumer unit and the glow remains.

Anyone have any thoughts as to what could be going on?

Synopsis:

• House running on battery, grid down with broken cable
• 3 sets of lights glowing on separate circuits
• MCB's on/off make no odds, even if all breakers are off it glows

nimrod86

Even this fused switch with a neon indicator for the oil boiler is glowing, though funny enough he says there's about 6 of them throughout the house and this is the only one doing it?

MrMusician18

I think this can be a symptom of a floating neutral

BuzzG

I have similar behaviour when running off grid (on battery power).

10-10-20

https://www.boards.ie/discussion/comment/123118827#Comment_123118827

What earthing arrangement do you have and what inverter?

Paul Kiernan

This is potentially (pardon the pun!) dangerous as you can get 115v between the earth and the neutral. Read up (in other threads) on the necessity of bonding the earth to the neutral if the neutral is disconnected from the grid as part of the "grid disconnect".

nimrod86

Himself got onto the crowd that installed the system today, and here's what they said to him:

They just rang me back.. something completely normal when having an inverter. It's called mutual-induction. Basically a magnetic field around the cables coming into the fuse board gives off pulses of power than induce power in the neutral wires. It's in the neutral wires so the breakers don't stop it as they are live wires. Nothing to worry about and it's the tiniest bit of power that LEDs are sensitive to. So nothing to worry about and nothing to fix. It just happens randomly and could happen some days and not others etc.

Fairly sure the earth to neutral bonding is done on his setup, and the explanation more or less makes sense, though if anyone here can explain reasons why it would start all of a sudden that'd be great for my own curiosity!

He has also noticed at night when running water pumps they make funny sounds on battery that they don't with the Grid, but it stops if he disconnects the panels (even though they're not generating at night). I reckon it's to do with the AC frequency output by the inverter and I've 230v frequency meters here at home so next time I visit I'm gonna connect it up and see what difference there is between Grid power, and inverter with/without panels connected. Again, more for my own curiosity than anything else!

JohnySwan

Doesn't sound right to me, on a properly earthed neutral, you won't see an induced voltage.

Use a socket tester or check the voltage between neutral and earth.

JohnySwan

https://www.boards.ie/discussion/comment/123121576#Comment_123121576

Were the panels wet at the time?

10-10-20

https://www.boards.ie/discussion/comment/123122226#Comment_123122226

I'm hypothesising here but this might be true for circuits where there are neutrals and lives run together as they cancel each other, but I'm not sure that it still applies when there are no neutrals at the switch, there could be additional capacitive current which doesn't get inversely negated on the neutral. Thoughts?

JohnySwan

https://www.boards.ie/discussion/comment/123122443#Comment_123122443

Potentially, but that wouldn't explain the lighting neon on the spur.

BuzzG

https://www.boards.ie/discussion/comment/123118904#Comment_123118904

@10-10-20 - I honestly don't know the earthing arrangement, I would assume it's whatever the standard is. The inverter is an Alpha ESS inverter.