RCD problems

[tscollet]

About a year ago we had a new consumer unit installed by an electrician fitting out some kitchen changes, and with this came an RCD (Wylex 80A 30ma). Ever since we have had nuisance tripping - it trips on average once a day.

The original electrician has ceased trading, and we have had 2 further ones out who have tested all the sockets & some appliances, only for the problem to continue or day or 2 later. Here are some of the symptoms;

1. often trips when a light switch is turned off (even though the lights are not protected by the RCD)
2. Happens whether people are in the house or not
3. We have unplugged every appliance when away on holiday & returned to find that the RCD has still tripped
4. Usually trips in the daytime, only on a couple of occassions has it happened at night


I do a bit of DIY but usually leave electrics to the professionals - can anyone suggest anything that I can try myself, or any suggestions on what I could ask another electrician to do?

 

[Steve]

Did the electricians test the RCD itself? If not this is the next step.

The problem with RCDs tripping is that it is often hard to trace the fault, as it can happen randomly.

 

[tscollet]

Thanks Steve - I don't believe the electricians did test the RCD, they thought it had to be a problem with the sockets or an appliance.

Is testing / replacing the RCD something I could do myself?

 

[securespark]

Only with the right kit.

Is it a split-load board? If so, check that all neutral wires are in their respective 'bars.

IE, all neutrals on non RCD side are in the correct N bar (not fed from RCD), and all RCD neutrals are in the bar fed from the RCD.

 

[Steve]

Beware even with the mainswitch off, the incoming tails to the consumer unit are 100% live (but they shouldnt be easy to touch). If you have an isolation switch before the CU, use it.

 

[JohnD]

have a look for damaged cables. this can be: nail through wall or floor; heavy appliance e.g. cooker standing on its flex; mouse-gnawed insulation esp. under kitchen floor. This is more common when a new CU has been installed on old cables.

look for anything that might be wet - outdoor lamps or switches exposed to rain

see if you can isolate the immersion heater and the boiler - water and electricity tend to cause earth leakage.