DIY Doctor


Postby brettWHITMILL » Thu Apr 01, 2010 5:57 pm

HI just had a 80 amp 100ma rcd fitted betwen meter and cu. the cu is a split board which is protected by 80a 30ma. The problem is that the main 80amp 100ma is random tripping(sometime up to 5 days) and therefore cuts power to everything. Can i remove this and replace with a switch and the circuits that are not rcd protected put in rcbo's? or is there a better way?
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Simply Build It

Postby ericmark » Fri Apr 02, 2010 2:30 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.
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