On 29/12/2017 12:20, John Rumm wrote:

It would probably only take 15 mins to go through each circuit in the CU
and do a quick N to E resistance check...

(i.e. turn off MCB, disconnect circuit neutral(s) from bus bar, and
measure resistance to earth (of if you have an insulation resistance
tester measure N+L joined together to earth))


Did this a few months back when we were chasing an intermittent tripping
fault with the oven, which turned out to be a grill element.

Only change made as a result of trying to fault find that issue* was to
replace the MCBs with RCBOs, of course that could well be the issue in
itself but it's been fine for the several months since then.

*I posted about it tripping the RCD as the oven was turned off. The
suspicion from the start was grill element but it never showed up on IR
checks, hot or cold. Put cooker on non RCD circuit and the grill element
eventually failed in a nice shower of sparks and melted metal