RCD tripping Continuity test

[coatesykid]

Hi, am doing a continuity test on living room light, downstairs MCB off, last light in circuit, incoming to light disconnected, disconnect switch twin and earth, cross connected Earth and neutral in switch, did a continuity test at light and the RCD trips.


Any help appreciated, only thing I could think of is that the current sent from tester is leaking out the switch cable into another cable and tripping RCD.

 

[Octopus]

Silly question but you have disconnected the L & N from the CU haven't you?

 

[coatesykid]

Silly question but you have disconnected the L & N from the CU haven't you?

should it mater all im doing is testing a cable that isn't connected to any thing at either end

 

[tony mc]

Well if the RCD is tripping it is seeing a imbalance on the system so it does matter if you think it is not connected have another good look at it !

 

[Brightspark2]

should it mater all im doing is testing a cable that isn't connected to any thing at either end

Looks like its still connected then...somehow...

 

[Sintra]

should it mater all im doing is testing a cable that isn't connected to any thing at either end

Of course it matters if the cables are still connected in the consumer unit. Soon as you join N & E together at other end it will trip he RCD.

 

[Brightspark2]

Oops just re-read I thought he meant the cable wasnt connected either end.


As sintra said if its still connected in the consumer it will trip. You've only disconnected the line conductor, neutral and cpc are still connected.

 

[MDJ]

Hi, am doing a continuity test on living room light, downstairs MCB off, last light in circuit, incoming to light disconnected, disconnect switch twin and earth, cross connected Earth and neutral in switch, did a continuity test at light and the RCD trips.


Any help appreciated, only thing I could think of is that the current sent from tester is leaking out the switch cable into another cable and tripping RCD.

please Expand LOL

 

[coatesykid]

please Expand LOL

I Made a mistake in first post said tested natural and earth ment switch live and earth.

Ill try and explain better twin and earth which includes switch live, live and earth, from switch to ceiling rose disconnected at both ends so its isn't part of the circuit, continuity between live and switch live good, continuity between earth and switch live trips RCD

 

[44ALLAN]

Take the bulb out

 

[coatesykid]

the cable im testing isnt connected to anything

 

[44ALLAN]

the cable im testing isnt connected to anything

It must be mate................unless you have a ghost

 

[guest119]

the cable im testing isnt connected to anything

Yes it is.
Is there another light you can see or one you cannot see, perhaps a patched up old wall light connection with its own neutral?

 

[i=p/u]

I'd say we have all done it , working on dual board and knocked breaker off fixing something and not even known conductors have touched.. I've done it anyway and when turned on, go wtf for split sec....

 

[coatesykid]

could be but its my dads house and hes lived they 30 years and there has never being any wall lights and he had it rewired 25 years ago

 

[Wiresandthings]

Maybe the old borrowed neutral issue, and through the lamps??? this also causes a tripping issue when a CU is replaced and you split the up and down circuits across two rcds, just a thought!!

 

[coatesykid]

-

yea but its being 18 months since I change C.U




sorry guys having trouble typing on the site keeps missing letters out and jumping about

 

[Wiresandthings]

It HAS to be connected to the CU somehow, by some means, no other way it can trip

 

[coatesykid]

im going to take up boards tomorrow and rewire

 

[44ALLAN]

Must admit I tested a cable at work the other day and it tripped the mcb on my kitchen sockets 5 mile away..............very strange