Neutral Fault - new wiring.

kegnkiwi

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Hi All

Just had a load of new wiring done in a granny flat making it into a new kitchen. Got lots of new junctions in and 10 new gu10 lamps and holders put into the roof. As part of this we have had a new consumer unit put in to keep up to regs. Problems is there is a fault that has arisen on a upstairs lighting circuit. Our electricians says its a neutral fault and it keeps tripping the rcd on the circuit board. But there seems to be more and I'm trying to work out if the new board is overloaded as if I put say the kettle on or a vac then the rcd trips on the lighting circuit. Our sparky is due back hopefully this weekend to rectify the issue but I am trying to work out where we could have a faulty consumer unit.
 
if its a split load box the neutrals may be crossed over causing the trip
 
Hi Ian is this what you call a split load box, it has two rcd buttons?
 

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Yes mate. Im no spark but through personal experience ive had the fault of tripping I wired a socket in to the leccy cupboard and it kept tripping. The fault put the live in one side of the split load box and the neutral in the other by mistake.
 
maybe the neutral for upstairs light is on wrong neutral bar, thus causing tripping
 
Yep, split-load 17th edition board. Unlikely to be faulty assuming the RCD passed trip tests. Most common faults are:

1. Live and neutral of one or more circuits on opposite sides of the split
2. Neutral 'robbed' somewhere i.e. used a neutral from circuit on the other side of the split
3. The board is of a type that requires manually splitting

You can easily tell if it's three. Whip the top off, look at the bottom of the trips. There should be two seperate bus-bars, one from each RCD. Some boards supply a single bus-bar and expect you to cut it. This allows you to divide the circuits more flexibly rather than just six trips on each side etc.
 
Our sparky has not been back yet so decided to try and test a little today, went into the loft and removed all the neutrals out of the upstairs lighting circuit junction box, turned the circuit back on and still the problem exists so put them all back in line and will wait patiently.
 
The sparky found the fault today it was a neutral to earth fault on a light upstairs but it was in another extension. The neutral wire sheath had a break and when the case was pushed up it opened the gap and touched the case which was earthed. The old circuit board did not pick it up but on this new board it trip straight away.
 
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