Sure, if an N-E fault somewhere were of sufficiently low impedance that a non-faulty boiler tripped the RCD, then a kettle certainly would as well. However, as I went on to say, I was talking about a 'faulty' boiler (or, at least, one which resulted in a small leak to earth). In that situation, if the circuit fault of was of sufficiently high impedance that a kettle didn't result in a trip, a 'leaky' boiler might be the 'final straw' which resulted in a trip.Not if it is a circuit N-E fault and a non-faulty boiler trips it then, surely, a kettle would.It depends upon the extent (impedance) of the fault, doesn't it?
Yes - but, if it's really true that there were absolutely no connected loads (connected to the RCD, not just the final circuit in question), the only place for there to be any leakage to 'accumulate' with that from the boiler would be in the circuit itself, wouldn't it?Yes, that makes sense and may, indeed, be the solution - but that would also be the case with just accumulated leakage without a circuit fault.You seem to be thinking of a low (maybe even negligible) impedance N-E fault - in which case, as you imply, connecting almost any significant load (not just the boiler) ought to result in a trip. However, if it were a very high impedance N-E fault (only detectable by IR testing), it might never, in itself, be enough to result in an RCD trip, even if large (but 'non-leaky') loads were connected - but the RCD could trip if another load with a small leak ('the last straw') was connected.
No - as above, if the impedance of the circuit fault was high enough that a (non-leaky) kettle did not result in a trip, it's still possible that a leaky boiler would result in enough accumulated leak (circuit+bolier) to result in a trip, isn't it?Surely "a very high impedance N-E fault" that resulted in a boiler tripping the RCD could not sustain a kettle.
As I'm about to ask the OP again, he has to ensure that nothing protected by the same RCD is 'plugged in'/connected - not just things plugged in to the final circuit in question.Have we definitely determined that the boiler trips this one circuit with nothing else plugged in to it?
As I said before, you don't have to only unplug/disconnect/isolate everything on the same circuit - you have to do that for anything/everything on circuits that are served by the same RCD - depending upon the arrangement of your CU, that might involving switching off all lights and isolating things like cookers, immersion heaters etc. (and anything plugged into any other sockets circuit served by the same RCD).Yes I have tested the boiler with everything unplugged on this circuit. It trips.Have we definitely determined that the boiler trips this one circuit with nothing else plugged in to it?
The only thing I wondered about that suggestion is that it requires at least two faults, doesn't it? ... firstly a fault (or, at least, problem in the installation) that means that the boiler provided a better path to earth than did the CPC/MET and, secondly, some fault which resulted in current through the earth path?Deadshorts suggestion sounds right (in my unqualified opinion!)
That seemed to be what deadshort was implying - I can't think of any other way in which a boiler would provide a better path to earth than the MET - which is what he said.I agree. Doesn't that mean the proper earth path is not good enough or missing?
Sure - but I'd still count that as 'two faults' - (1) N-CPC fault and (2) CPC not connected to earth (until boiler plugged in). Wouldn't you?But electrician found a fault in a socket. ... It could have been socket screw contacting neutral with cpc (still?) not earthed but connected to boiler.
Who knows?! The worry obviously is that if both those faults were present, but only the N-CPC fault has been rectified, 'all might seem well' (in the absence of proper tests) even if a serious deficiency in the earthing remains.Oh, yes, not questioning that. However, have they both been rectified?
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