Why would circuit breaker trip every few hours?

scarletjim

Yesterday my GF texted me to say the electrical sockets and TV etc had 'gone off', then come back again on their own half an hour or so later. I thought nothing of it. Since then it's happened twice again - about 2am last night (I know as my housemate said his TV turned itself off about 2am) and this afternoon. This morning I went to the RCD box, and none of the switches appeared to have tripped. So I turned off the main controller switch, and all the individual switches, then put them all back on, and the electric came back on again. Then about 3pm, same happened again. This time, when I turned all the RCD switches off and on, it didn't correct the problem, well not at first anyway. I tried a few other ways, doing them one by one, waiting for a few mins etc, and after about 15 mins it worked. I can only assume that what caused it to trip had abated after those 15 mins...

Given that we have hundreds of things connected in the house, how / where on earth do I begin to identify the problem? It only happens every few hours, so I can't just unplug everything then put them in one by one to see what trips it.

Also, why don't any of the switches go down when it trips? That's not normal is it?

Cheers to anyone who can help (I'm happy to give further info, but please bear in mind I know nothing about electrics, so I'm happy to unplug appliances etc, but nothing technical).

Kiran

Are you saying the MCB's all stay up but the RCD trips out? If it's happening regularly then it could well be something overheating. It cools down when the power goes off and then overheats as it turns back on over a period of a few hours.


I may well be a mile off the mark but just a guess

scarletjim

Yes that's right, that's what's happening.

The thing is, I can't think what kind of device would overheat, then cool down enough to be fine 15 mins later, and then not overheat again for another 5 hours or more. Plus it happened at 2am - does that mean it pretty much must be something to do with the boiler and/or heating system? Nothing else is doing anything significant at that time (plenty of devices on standby obviously, but doubt that would do it).

Kiran

Next time it trips out put all the MCB's to the off position straight away and reset the RCD. Put the MCB's back on one at a time, hopefully one of them should trip the power again. That'll identify the circuit that has an issue. From there it is a case of checking everything on that circuit but it does eliminate the rest of the house.


As I say, I'm not an electrician but this should work

stator

If you're RCD tripped it wouldn't come back on it's own, you'd have to reset it.

Mojisola

scarletjim wrote: »

This morning I went to the RCD box, and none of the switches appeared to have tripped. So I turned off the main controller switch, and all the individual switches, then put them all back on, and the electric came back on again.

Also, why don't any of the switches go down when it trips? That's not normal is it?

If none of your switches have tripped, could it be a problem with your supply? Have you asked any of the neighbours if it's happened to them?

We recently had a series of short power cuts much as you describe.

Risteard

You obviously need to ring an Electrician. Surely that was obvious to you?

Grenage

I once had this occur with a shower RCBO, it didn't actually flip, it just stopped allowing much current through (enough for the isolator light, but not the shower).

I had a sparky replace the RCBO, and all was well. I'm not saying it's your problem, but RCDs do go wrong sometimes.

keith969

Sounds like a temporary power cut. Check next time if there is a known problem in your area: http://www2.nationalgrid.com/UK/Safety/Power-cut/

Risteard

Grenage wrote: »

RCDs do go wrong sometimes.

From experience an RCD almost never fails in such a way as it trips for no reason. It is almost certainly an earth fault causing it to trip as they are designed to protect against.

Crinkmeister

If it's not a power cut then faulty RCD or a loose connection somewhere would be the next most likely cause.