have plugged in a garden water pump into the garage socket now the rcd keeps tripping, rewired eveything and turned the garage switch off (in consumer box) whilst doing the wiring but the rcd still tripped i am baffled could it still be the pump if switched off all my sockets and showers are on this cu + rcd any help

simon, October 2008

i agree with stu but the pump needs an RCD as it is outside the equippotential zone.

mick, July 2009

I suspect the pump is leaking a little current it doesnt take much to trip these things. Try the pump in someones house who doesnt have an RCD if the pumps ok consider fitting a switch and do away with the RCD.

n, November 2008

Are you saying that you have a separate sub -consumer unit in your garage and even when this is switched off, the rcd at the main consumer unit in the house is still tripping?
Note you say your showers and sockets are on same rcd. A shower must be protected by it's own separate 4OA/30mA RCBO (or else RCD with an MCB) - not lumped together with sockets. Also if there is more than one electric shower they need to be interlocked to avoid overloading the supply (although that's not relevant to your present problem).

J, October 2008

hi simon there are a few things which may cause this but you should start with the most obvious the pump is probably causing the trouble as you had no trouble before it was installed? The pump may be causing a short between neutral and earth which would trip off the Rcd even if switched off. You should completley disconnect the wiring to pump and try your re-setting your RCD.Also you should check the wiring enclosure on the external wiring to pump as if there is moisture present this may be causing problems.But if in doubt call a sparky out a decent sparky should be able to find the problem with out to much trouble.

Stu the sparky, October 2008