RCD tripping out when dishwasher on

[gbrown100]

Hi,

Last night my RCD tripped whilst both the dishwasher and washing machine were on. The MCB for the circuit they are on did not trip, just the RCD.

Firstly, why did the MCB not trip also?
Secondly, what could be the cause? - I turned off the dishwasher and the tripping stopped. When I reset the RCD it took about 10 seconds before it tripped again.

Thanks

Graham

 

[lostthewill]

mcb didn't trip because it provides overload / short circuit protection.
rcd provides earth leakage protection.
possible causes? loose connection, even the earth. unplug the dishwasher and try again. then unplug the washer and try again. could be an appliance going faulty. failing that a sparky can test the rcd unit and the wiring.

 

[ColJack]

from the description, you've got water inside the dishwasher where it's not supposed to be..

time to strip it down and have a look, or get the repair guy out, or get a new one..

or are you saying that the RCD still tripped with just the washing machine switched on?

 

[TicklyT]

RCDs usually respond to faults that cause electricity to leak to earth, possibly as a result of water from the machine having ended up somewhere it shouldn't, or failure of a machine part that's in direct contact with the water, like a heater element.

Best to unplug the suspect machine rather than just switch it off. The switch may only break the live connection. RCDs monitor current in both Live and Neutral, so they may still trip if the fault is between Neutral and Earth.