Major problem - am I missing something??

[sivoodoo]

Hi all,

Ive just installed a new split load CU, lots of old circuits in the house, every circuit works ok except one (a kitchen ring, recently installed but not by me).

The problem is this:
I conect the lives of the kitchen ring to the mcb and the earths to the earth bar, but when i touch the neutrals to the neutral bar the RCD trips.

I swapped this circuit over to the other RCD side and it happens again.

If I remove the earths of this circuit I can happily connect the neutrals with no tripping, but soon as i touch the earths to the earth bar it trips the rcd again.

Insulation resistance is good.
But there is continuity between earth and neutral on this ring.

Ive had every socket off the wall and they have been wired correctly.

What am i missing, i will be going back in the morning so any tips pointers wil be very much appreciated as Im tearing my hair out!

Thanks,

Simon.

 

[Deleted member 9648]

How can IR be good when you have 'continuity ' between N and E ???.....Sounds like there is a low IR N-E.

 

[Amp David]

If you have N-E continuity how can you Ins Res be OK?

 

[Amp David]

Beat me to it haha

 

[Hawk81]

definitley neutral to earth fault. is there anything spured off the ring? outside light, heating, etc.

 

[sivoodoo]

doh!, yes IR between E and N is 0. Fine between L and N.

 

[Amp David]

Start by breaking the circuit down into sections and retest.

 

[sivoodoo]

The split method, yes ill do this tomorrow, thanks.

 

[robsparky1975]

Its a good idea as has been quoted on here before to dead test on n-e and l-e before upgrading ccu,saves time in the long run.

 

[Amp David]

Dont go diving into it either. Get a brew first and take it one step at a time.

Its to easy to confuse yourself and you end up going round in circles.

 

[telectrix]

had similar.was outside socket spurred off kitchen ring. So called IP65 box cotaining extn. lead feeding garden lights and pond pump. opened box. hair dryer and resealed. end of N-E fault

 

[sivoodoo]

Thanks for the good advice, i shall let you know the results if i ever work it out!

 

[Johno]

It will more than likely be a neutral touching the KO box, I would just unscrew all easy to access sockets first and keep my fingers crossed.

 

[telectrix]

and look for nails in walls hanging pics etc.!!

 

[sivoodoo]

Ok sorted it today.
i split the ring down to the last couple of single skts, disconected them tested and the problem went away, re conect the skts and everything is ok, could not see any niks in the insulation, scratched my head, wired up the CU and no problem. All good! moisture perhaps? an invisible gremlim?? god knows but now its fine??
Thanks for your replys!

Simon.

 

[UNG]

Box screw shorting on the neutral possibly

 

[Gravid]

Box screw shorting on the neutral possibly

Sounds favourite, had two of these last week on the same cct. Funny thing was she'd just got new wireless phones and they hadn't been working right, once I cleared the faults they worked fine, whats that all about ?

 

[Sav]

Maybe EMF ???
That may afect the phones??
Just a thought...thats all,
Sav