Tripping rcd

[NeonSparks]

just moved an mcb to rcd side of board and now a lighting radial on NON rcd side trips rcd...any ideas? I'lm sure i have moved correct wires.

 

[olly w]

Sounds like a borrowed neutral.
What circuit was on the mcb that you moved?

 

[Sintra]

Have you moved the neutrals onto the correct bars in the cu or else it could be a borrowed neutral between the circuit you moved and the lighting circuit.

 

[NeonSparks]

it was the upstaire lights(fitted downlights to bathroom) .....the downstairs lights trips

 

[Sintra]

Borrowed neutral between the 2 lighting circuits.

 

[NeonSparks]

so a neutral from downstairs joins with N from upstairs you think?

 

[NeonSparks]

so the only way to sort it is to find link and (cut it)?

 

[olly w]

I would guess that the neutral as been borrowed for the two way switching for the landing.

 

[Sintra]

Absolutely the landing light is probably on the downstairs lighting circuit due to the 2 way switching but the neutral will be taken from the upstairs circuit.

 

[bugsy]

Yes, line from ground floor 2 way feeding landing light and return on 1st floor lighting circuit

 

[NeonSparks]

ah ok. that gives me something to go on......thanks for all the quick replys!

 

[NeonSparks]

would that make it trip on its own or could there be an earth fault on that radial?

 

[bugsy]

If its a borrowed neutral thats the problem and if as you have said it only started after you repositioned the mcb seems crystal!

 

[shirlock]

Can't you put both lighting circuits on rcd side and note on cu about borrowed neutral if customer doesn't want to pay for fault finding?

 

[NeonSparks]

lol ok cool...thanks for replys

 

[bugsy]

out of curiosity why did you move the mcb

 

[NeonSparks]

because a bathroom radial has to be on an rcd?

 

[Hawk81]

Can't you put both lighting circuits on rcd side and note on cu about borrowed neutral if customer doesn't want to pay for fault finding?

surely you cant leave a borrowed neutral. either find the borrowed neutral and fix or put both lighting circuits onto the 1 mcb.

 

[Marvo]

If two circuits are sharing a neutral you can move both the circuits to the RCD side of the board along with their neutral(s) and peace and harmony should be restored.

 

[Hawk81]

If two circuits are sharing a neutral you can move both the circuits to the RCD side of the board along with their neutral(s) and peace and harmony should be restored.

i would not say peace and harmony are restored by leaving a borrowed neutral as this is dangerous. surely not great advice!!