RCD Tripping.....

[dlt27]

Can anybody help... Went to a job Friday where apparently RCD is coming out once every couple of nights. The rcd covers 4 circuits which are sockets, sockets, heating and outdoor shed. I have carried out a blanket test and I am getting a reading of about 20M This is with loads conncted apart from 2 neon extension leads which if connected brings it down to 0.39M.(still to high to cause tripping). I have also done a ramp test on rcd and it comes out at 23mA. Finally put clamp meter around tails serving rcd and with loads connected was still only getting 10.5mA of earth leakage. Thanks for any advice.

 

[shanky887614]

Can anybody help... Went to a job Friday where apparently RCD is coming out once every couple of nights. The rcd covers 4 circuits which are sockets, sockets, heating and outdoor shed. I have carried out a blanket test and I am getting a reading of about 20M This is with loads conncted apart from 2 neon extension leads which if connected brings it down to 0.39M.(still to high to cause tripping). I have also done a ramp test on rcd and it comes out at 23mA. Finally put clamp meter around tails serving rcd and with loads connected was still only getting 10.5mA of earth leakage. Thanks for any advice.

what kind of loads are connected

 

[dlt27]

Washing machine, freezer, electric fence fed from shed, kettle, boiler. Even ran up heating but earth leakage still didn't go above 10.5mA. Did mention fitting rcbo's but if its an appliance breaking down this wouldn't help( just cause more expense).

 

[amlu]

temporary replace mcbs for rcbo. see which one trips to narrow the fault.

 

[dlt27]

Would if I had some..

 

[Richard Burns]

From your testing the circuit wiring seems OK, therefore you are now heading for connected equipment with an intermittent fault, always a nightmare.
You probably need to do some investigation of the times and weather conditions when the RCD trips. If the trip is over night then it is only likely to be items that are running overnight.
Because some of the items are outside it could be water ingress, since you have 10mA already you only need another 13mA to trip it.
Could the electric fence be shorting when something pushes against the fence.
Freezers can be prone to tripping RCDs when old, less likely, but maybe you could run the freezer on an extension lead from another circuit for a few nights and see if the other circuit trips.
Did you run the ashing machine as these often break down to earth, but only when X item is activated, do they run the machine overnight?

 

[Octopus]

Get the client to unplug as much as possible and see what happens?

 

[GT1]

Seems lot of stuff in the outdoors there..!!
I'd be looking there first to eliminate them from my enquiries..

 

[jackhammerJIM]

electric fence on an rcd is an interesting idea, touch the fence i bet it trips the rcd

 

[dan86]

been back to the job yet OP?

 

[telectrix]

freddie the fox strikes again.