by ericmark »
Fri Apr 02, 2010 3:30 am
100ma RCD's don't normally trip and I wonder it there is a bad connection somewhere which is causing it to trip?
With TT supply any RCBO will need to be twin pole and so it may not be an option?
An RCD for use with a TT system need not be 100ma and since 300ma is value for fire protection you may be able to fit a higher value but the resistance of the earth rod will be main factor here.
But I would be testing all I could and looking for lose connections as in the past this has often been caused by someone not tightening up screws and if not found it could cause a fire.
Testing the RCD would also be good idea and I don't mean the test button but with a RCD tester. Likely cheaper to get an electrician to test it for you than to hire or buy the meter required.