[Closed] sparky question

RCD will trip if you short neutral and earth together while working on circuit - breaker only isolates the live side

hmmm possibly I.may have shorted whilst adjusting the wire lengths.  is there a way of checking?  all seems fine....could just be being paranoid

Of course you have a test kit and the knowledge to dead test so you can safely proceed to switch on the circuit...

As above or maybe if you have a dual RCD Split load board you have put your neutral on the wrong neutral bar, if you have been wiring from the CU.

Guess best you can do is visually inspect and switch on, If it’s N-E problem it just won’t reset.

<p>Rcd will trip if you earth the wiring as said, I ended up swapping my board about so lights and ring mains for each part of the house were on seperate sections of the board.</p>

thanks for the responses.  no I wasn't wiring from the cu.  just a junction box onto an existing light circuit and a new pendant and switch drop.  nothing fancy and have done similar many times in other houses.

doesn't seem to be any other issues if I turn the mcb off and leave it the rcd doesn't trip which strongly suggests it was me tripping the N E when wiring the junction box or light.

I don't have the skills to swap things round at the consumer unit, should I get the sparky back and say I want the 3 lighting circuits on one rcd and the mains loops on the other?  I didn't specify that to him so hard to say he did anything wrong unless.its not best practise?

If it was a one-off I wouldn't be worried about it, especially if it happened simultaneously when you did some work.

should I get the sparky back and say I want the 3 lighting circuits on one rcd and the mains loops on the other?  I didn’t specify that to him so hard to say he did anything wrong <span class="skimlinks-unlinked">unless.its</span> not best practise?

You don't want that. If you have a split load then its best to have lights and circuits split between them so if one goes you still have some power and lighting on the other. Ideally upstairs lighting and downstairs sockets on one, downstairs lighting and upstairs sockets on the other.

ah ok.  I have ground, first floor sockets and ground lighting on one rcd and the rest on the other.  Sounds like he did the right thing then.  just a pain as it trips the alarm if off too long

some more work to do today as want to fit 2way switching so will be more careful with the N and E and see if it happens again

As I understand it, nothing trips in use, either before you extended the circuit or after you've re-energised it, but the RCD tripped while you were working on bared wires with the MCB out, and you might have shorted earth and neutral while doing it. Neutral to an earthed metal pattress box is easily done. All that suggests to me is that you did short them and the RCD works as it should. No fault, no need to rewrire anything.

IANAS.

Thing is neutral earth faults can be on a circuit that you think is fine (shared neutral and earth Cabling at the incommer) so the only real way to establish which circuit you have a fault on is to start disconnecting the neutrals from the board one by one until you can reset the RCD. Then once you know which circuit it is for sure the fun starts and floor boards come up ( and then you find it was just an appliance) trying to find the errant Cabling.

Neutral to an earthed metal pattress box is easily done. All that suggests to me is that you did short them and the RCD works as it should. No fault, no need to rewrire anything.

Yep, done this loads.

Much prefer the French system where the isolation switch isolates L & N....