Nuisance Tripping

[s6stu]

Hi people,

I have been asked to investigate a problem regarding the tripping of an RCD at a customers house, which has apparently become increasingly worse. The fuse board was fitted, by an electrician, roughly 8 years ago. For some reason he fitted an RCD main switch, no split load, on a TN-S system. Is there a good reason for this?

Anyway, the tripping seems to occur at random times, (sometimes at night) and not on the activation of a particular circuit. The only obvious thoughts that come to mind are either a loose connection somewhere or breakdown in insulation?

Any suggestions?

Thanks

 

[wayne]

what size rcd? more info pls

 

[Grae79]

bit of testing required methinks

 

[Shakey]

Hi people,

I have been asked to investigate a problem regarding the tripping of an RCD at a customers house, which has apparently become increasingly worse. The fuse board was fitted, by an electrician, roughly 8 years ago. For some reason he fitted an RCD main switch, no split load, on a TN-S system. Is there a good reason for this?

Anyway, the tripping seems to occur at random times, (sometimes at night) and not on the activation of a particular circuit. The only obvious thoughts that come to mind are either a loose connection somewhere or breakdown in insulation?

Any suggestions?

Thanks

Hi

a loose connection wouldnt cause an RCD to trip. I would look for something like an outside light or an external socket that has got water in it, or something like a bit of twin and earth that has been run to shed at the bottom of the garden, that has been 'shovelled' or chewed (seen it before!). "progressively worse" excludes wiring faults so is generally degredation of some kind

be useful to know what circuits are on there

it could just be something dodgy plugged into a socket, but it would mean unplugging everything or switching off the ring for extended periods to see if the fault reoccurs

 

[s6stu]

Hi,

haven't replied as I've only just managed to start the job! You know how it is e.t.c...

I started by checking the details asked for here, nothing unusual circuit wise, sockets lights. The RCD is an 80A rated, 30mA operation. However, shock horror, there was no earth conductor!! I've obviously installed one now, I assume this would cause the tripping? Not sure about the tripping becoming progressively worse, perhaps they were becoming progressively more fed up with it!

Also, as a side question, I suppose the RCD was tripping due to the earth leakage elsewhere on the circuits being seen as a fault?

 

[stevie h]

sounds like water , pond pump , out side light/socket maybe

ste