Hi everyone.
This has been an off and on issue for quite a few years, and seems to return for short periods of a few days or weeks and then goes away for months even a year or more. During the dodgy spells, the RCD trips at pretty random times - it was just after 10pm last night, after we'd all gone to bed. On other occasions it would happen in the mornings, at around 7am, even tho' nothing was being switched on at the actual times.
Weather seems irrelevant - it's been warm and dry here for the past couple of weeks; on other occasions it's been wet and windy.
The RCD can usually be reset successfully, tho' there have been times when it would trip again quickly, and I would then try isolating circuits until it would stay 'on'. The randomness of it all, however, means that it decides itself when to stay 'on', and the circuit I'd isolated at the time was a red herring. (I was darned sure it was the outside lights on one occasion, as isolating this MCB seemingly 'allowed' the RCD to reset. With the ext lights MCB still 'off' for a couple of days while I checked the wiring, the bludy thing tripped again...)
We had an extension built last year, and the sparky did his normal check on the house wiring before extending the socket and lighting circuits for this, and clearly didn't find anything of concern, tho' I didn't point out the issue we'd been having as they just hadn't happened for a year or so before then.
As there is no single circuit I can isolate via their MCB that stops this happening - tho' I haven't been able to check them all as the issue is so random and infrequent - I suspect it's a 'cumulative' leakage in many circuits which is building up towards the '30', and then something - an external 'spike' or summat? - trips it over the edge. For instance, during one spell it would happen at around 7-ish (I think it was) each morning, but there was nothing in the house being switched on at these times. Sometimes it would refuse to reset for a couple of goes, then it would be fine, and stay fine. Other times it would reset the first time, and either stay fine, or trip again 20 minutes later (as it did this morning).
To sum up - no single circuit being isolated has stopped it from happening. There is nothing in the house that can be pinpointed as coming 'active' at these times.
I'm considering having our stupidly large double CU (16 MCBs... 7 do just 'lights', a few rooms each) rationalised down to, say, a 12-way CU with RCBOs, so that they share the leakage. Would this be a reasonable move? I'm guessing the cost would be - what? - £800-ish?
Or is it possible for the MEM A100HE RCD to be faulty - too sensitive?
Thanks.
This has been an off and on issue for quite a few years, and seems to return for short periods of a few days or weeks and then goes away for months even a year or more. During the dodgy spells, the RCD trips at pretty random times - it was just after 10pm last night, after we'd all gone to bed. On other occasions it would happen in the mornings, at around 7am, even tho' nothing was being switched on at the actual times.
Weather seems irrelevant - it's been warm and dry here for the past couple of weeks; on other occasions it's been wet and windy.
The RCD can usually be reset successfully, tho' there have been times when it would trip again quickly, and I would then try isolating circuits until it would stay 'on'. The randomness of it all, however, means that it decides itself when to stay 'on', and the circuit I'd isolated at the time was a red herring. (I was darned sure it was the outside lights on one occasion, as isolating this MCB seemingly 'allowed' the RCD to reset. With the ext lights MCB still 'off' for a couple of days while I checked the wiring, the bludy thing tripped again...)
We had an extension built last year, and the sparky did his normal check on the house wiring before extending the socket and lighting circuits for this, and clearly didn't find anything of concern, tho' I didn't point out the issue we'd been having as they just hadn't happened for a year or so before then.
As there is no single circuit I can isolate via their MCB that stops this happening - tho' I haven't been able to check them all as the issue is so random and infrequent - I suspect it's a 'cumulative' leakage in many circuits which is building up towards the '30', and then something - an external 'spike' or summat? - trips it over the edge. For instance, during one spell it would happen at around 7-ish (I think it was) each morning, but there was nothing in the house being switched on at these times. Sometimes it would refuse to reset for a couple of goes, then it would be fine, and stay fine. Other times it would reset the first time, and either stay fine, or trip again 20 minutes later (as it did this morning).
To sum up - no single circuit being isolated has stopped it from happening. There is nothing in the house that can be pinpointed as coming 'active' at these times.
I'm considering having our stupidly large double CU (16 MCBs... 7 do just 'lights', a few rooms each) rationalised down to, say, a 12-way CU with RCBOs, so that they share the leakage. Would this be a reasonable move? I'm guessing the cost would be - what? - £800-ish?
Or is it possible for the MEM A100HE RCD to be faulty - too sensitive?
Thanks.