Strange Wiring Fault Causing RCD To Trip

[Adam_151]

After we have discounted the reversed conductors, then (and trying to apply occams razor here), how about an open circuit neutral, 'back-fed' by a neutral->earth fault after the break

 

[securespark]

Rice

I've been using a Class II table lamp and it trips only when the socket & light is switched on.

RMS

Can see where you're going here, ie the introduction of a load at a point on a circuit can flag up a fault elsewhere, but surely, with all these circuits on the split side RCD-protected, can you explain why other loads introduced on this side of the board don't trip the device?

Even though I have nearly 20 years experience in the trade, I have managed to avoid this problem until now!!

 

[securespark]

After we have discounted the reversed conductors, then (and trying to apply occams razor here), how about an open circuit neutral, 'back-fed' by a neutral->earth fault after the break

Oooh, that's lateral thinking!

 

[ricicle]

When are looking at it again????

P.s You've been in the trade for about the same as me (19 years this year)

 

[festa]

Hmmmm unless ive missed it ......
Did you try a new socket faceplate just to discount the fact the old plate is buggered?

 

[suffolklad]

a friend had a fault like this one socket threw rcd trip when a socket was switched o sometimes not always might go a month then prob it was bad insulation on a live wire touching earth on back of socket you could just see where it had sparked on earth o back of socket. strange but it didnt always throw trip depended on load

 

[RMS]

If it is a N-E fault on that particular circuit then i don't think other individual circuits protected by the RCD would cause it to trip.

Although i'm sure i have been to jobs in the past where this has happened. Maybe someone else can explain this as i am not entirely sure.

The only way to tackle this sort of fault is with an insulation resistance tester and a bit of patience.

 

[securespark]

Hmmmm unless ive missed it ......
Did you try a new socket faceplate just to discount the fact the old plate is b*****r?

Yup. And replaced the RCD (cos it failed 5x), but neither made any difference.

Ricicle...20 years in September. Old F@rt that I am!!

 

[festa]

In that case my money is on either a faulty JB under a floor board or poor insulation in which case that super duper `megger` is gonna flash a bad result at you

 

[securespark]

Would be only too pleased if it did!

Ricicle, I go back on Mondberg.

 

[securespark]

Ha, ha!

It was the neutral shorting onto the wrong side of the board....

 

[joe-90]

Experience has taught me never to listen to customers. Thay talk complete bolix.