Random RCB trip on main split load circuit board.
no individual circuit appears to be responsible.
but will trip sometimes when cooker thermo static control comes on or off on oven. or if sometimes equipment is switched off around the house. The random trips could be fridges / freezers cutting in and out. No obvious faults with appliances. Plug sockets checked with plug in tester for correct wiring and earthing. suggestions anyone

gh, September 2009

test the rcd first. main culprate. then unfortunately its an appliance. most likely an expensive one like fridge freezer cooker washer.

andy, August 2011

sounds like aneutral fault to me, but im just an NIC reg spark dont listen to me.

sounds like a magnetic imbalance

dearest spark ever, November 2009

as an electrician who pat tests,could be earth leakage as other postings explained, could also be the rcd itself, when a rcd test is carried out part of the test involves testing at half rated trip ie, 15ma, if the rcd trips at this level it is replaced as this will cause otherwise unexplained tripping, the rcd test takes 5 min if a cup of tea is involved 30 sec if not.

sparkiefc, October 2009

Could just be too many appliances/outlets on one circuit. The RCD measures the total earth leakage current on that circuit. Once it exceeds 30 mA, the RCD trips. The individual leakage currents due to each appliance etc may be very small but when added together may exceed 30 mA. If everything is on one circuit this makes this more likely to happen.
Check immersion heater as well. If the element is in bad condition the leakage current from that will be increasing with time. Check kettles likewise and not just the element but modern kettles are detachable from the base which usually gets wet to some degree - again causing earth leakage.

J, September 2009

You may be best to get a GOOD electrician in - not just a domestic one but one that does PAT testing as well.
If the problem is not with the RCD it could be excess current leakage on your fridge, freezer, cooker, or even boiler if it is on the same side of the consumer unit.
A good electrician will have all the test instruments to test everything.

Adam, September 2009

Probably got nothing to do with your problem, but I have always had fridges/freezers on unprotected sockets. Then if a problem like yours arises they are not affected. Sorry can't be more helpful.

Harry, September 2009