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[allan.f]

My consumer unit keeps tripping and it is difficult sometimes to get it back on.It trips when nothing new is switched on,it may go for days without tripping,sometimes all three breakers are ok ( 1 for cooker,1 for sockets,1 for lights) whilst the main trip switch trips. If I turn everything off and start from scratch there is no pattern as to which appliance or circuit causes tripping.After about 30/40 attempts the sockets come back on then if I put the lights back on it trips again.If I reset the lights only it is ok until I reset the sockets.I think there is something wrong with the consumer unit.By the way I live on the ground floor and there are 2 flats above me (read that sharing earth pipes may cause problems).If it is the consumer unit how much am I looking for to get a replacement fitted bearing in mind I can't afford to re-mortgage?

[sparx]

Hi Allan, I take it it is the RCD main switch tripping, the reason it seems random is that you probably have more than 1 fault, the RCD looks for earth leakage of more than 30mA total, (in theory) but manufacturers err on side of safety & most trip around22/26 mA.
so if your cooker leaks say 15mA,(not uncommon),
then you only need say 10mA spread across all items plugged into sockets & 'bingo' your off!
Bearing in mind P.C's leak around 5mA each due to mains filters fitted it's a wonder RCD's ever stay on!
You may be right about 'external influences' as called, An insulation test should show circuit faults & if changing board go for main switch isolator plus individual circuit RCBO's for your 3 circuits, not the cheapest option but each circuit then has 30mA to trip it, & the dodgy circuit/appliance will soon show up, Regards SPARX