RCD

[T Smith]

A 30ma rcd has been fitted and protects 4 ring mains. Two of these are kitchen and garage.
The RCD is tripping but only it seems during the night. The garage has two upright fridges running on it (customers choice) and the kitchen has a small fridge plus kettle etc. Could the fridges be causing the problems or possibly a faullty RCD? Any ideas.

[Jimbo]

RCD can suffer tripping problems with Fridges very likely to be the fault, why not test the RCD and see if its holding in on the half current test? Regards Jimbo

[T Smith]

The RCD is holding fine @ 50% no problem, what I did do last night was take the fridges off the rcd side of the board. Talking to the customer this morning no problem, so far, lets hope this is the problem solved.

Thanks for your reply.

[Jimbo]

If you can get the fridges off the RCD side just stick fused spurs on them and the jobs a good un. On some jobs where the fridge / freezer is in the garage etc this is what I do saves a lot of worry when they go on holiday and the RCD trips. Regards Jimbo

[professorgbr]

Hi
I would do an insulation test both live conductors connected together to earth on the fridges as you have suspected them as they could have fault current going to earth

I had a simular problem with nuisence tripping so I carried out an insulation test on all RCD protected ciruits and found that there was low resistence between neutral and earth on 2 circuits I found a neutral conductor trapped at the back of a socket box and the other was a neutral conductor damaged by a socket front retaining screw when fitting the socket front
These 2 problems being rectified only reduced the frequency of tripping (what a *******) so then I PAT tested all the class 1 appliances the washing machine dishwasher and fridge all had problems resulting in earth fault current
a no trip loop tester tripping the RCD during a loop test could indicate that there is fault current going to earth but less than 15ma or whatever the RCD is tripping at