Umm strange...?

[sythai]

Done CU change recently, customer had already brought a 'nice' crabtree starbreaker...! Never been keen on these.

Been having bit of prob.

All tested and no faults on installation itself.

All fine on first 3module RCD all circuits holding in, but on 2nd 2module rcd along... 3 circuits on this as soon as turn on any of these 3 MCB's bang goes the RCD. First RCD stays in, so no shared neutrals there. So tried each circuit on first RCD side all hold in fine ?

Have tried taking everthing out CU except incoming tails and neutral links, then put each of these 3 circuits in on there own, on the 2nd RCD side and each one trips the RCD ?

Replaced the RCD and still same prob ?

Am I missing something ?

Could the internal busbar be faulty somehow

Cheers Sy

 

[Sparky Ninja]

Sounds like there could be a problem with the connection to the neutral supplying the second RCD?

 

[sythai]

Did check and re-check all connections.......... all links taken out and put back in .... really starnge this one ?

 

[Deleted member 9648]

We only use starbreaker on domestics and never had a problem...I can only think that the supply N to the second RCD is somehow incorrectly wired.........any chance of a pic of the configuration??

 

[jeremy]

I've accidentally mixed my neutrals up i.e. non-rcd neutrals to rcd neutral bar, rcd neutrals to non bar. rcd works by balancing line A and neutral A so should only operate if there is an imbalance. if a twin rcd board, temp swap rcd's to eliminate faulty rcd. Assuming fault still occurs, check circuit by circuit. If fault can't be isolated by circuit fault must be in DB.Please don't think this is an egg sucking class if you've already tried this !!

 

[rocker]

try putting the 3 suspect MCBs in the 1st RCD's bay temporarliy and see if they trip it.

You say youve removed everything but tails and neutral link... you have removed anything linking the two neutral bars when the two rcds are in use, havent you?

 

[Spudnik]

The link would only be in place if it was a standard spilt load, i think.

 

[sythai]

Got it all running temporarily on one rcd for now as cant get back for a short while.... will let you know how I get on when pop back, thank u for all your help suggestions, I'll get there in the end