Sockets tripping intermittent

[DavidU]

Hi all, I’ve reviewed as many forums as possible which could relate to my situation, but wanted to run through my scenario, maybe someone could shed some light. Please forgive my lack of understand in some matters, I only know what I’ve researched.

Main problem - socket circuit is tripping the boards MCB (not RCD). Have an old board looking around maybe the 80s. ONLY sockets tripping. Everything in home is on one circuit.

So, bought a house around a month ago and had intermittent trips on the sockets. I got an electrician round who tested the circuit. The things he found:
- there was a low current, but wasn’t concerned since I lived there by myself without much switched on
- there was a ‘resistance’ on the circuit. So tried to narrow it down and found it was coming from the boiler.

The electrician was sure it was the boiler causing the trips so he disconnected it from the wall and I was left without hot water for a few days.

Few days later, trips again. But this was a lot more frequent (within an hour 4 trips). During this time I disconnected everything to try to narrow down if an applicable is causing it. I got to a point where EVERYTHING was unplugged (fridge, oven, Washer, office upstairs, chargers, TV, router etc) nothing was in the circuit. Tripped again.

Electrician comes back out and suggests to move the wires from the current MCB breaker to a spare one to rule out a fault on the board. I thought this worked as I had no trips for a week. Started to relax and came home yesterday to find that it has tripped at some point throughout the day. Turned back on and 20 mins later tripped. Turned back on and was ok for about 6 hours, then tripped throughout the night.

I’m at a loss here, I’ve gotten to a point where everything has been turned off and unplugged (where I possibly can), electrician has suggested that it’s a ground fault so would need to check under floorboards, but had suggested that if he is doin that, I may as well get a rewire done.

I haven’t noticed a pattern, the time it trips seems to be very intermittent, and frequency is up and down as well. I’ve had to move back in with parents as I can’t work from home now.

Anyone have any suggestions?

 

[ericmark]

One can only guess, and so either rodent damage, so some thing not unplugged, the most likely is the freezer and it may have a fault only with defrost cycle, but in real terms if an electrician on site can't find it, we have no hope.

 

[crystal ball]

I had a similar fault to trace last year, found a slug inside a JB under the (laminate) floor.

 

[DetlefSchmitz]

Mice was my instant reaction.

 

[winston1]

Everything in home is on one circuit.

I've counted 10 circuits on that CU.

So, bought a house around a month ago and had intermittent trips on the sockets. I got an electrician round who tested the circuit. The things he found:
- there was a low current, but wasn’t concerned since I lived there by myself without much switched on
- there was a ‘resistance’ on the circuit. So tried to narrow it down and found it was coming from the boiler.

Not sure what he means by that.

electrician has suggested that it’s a ground fault so would need to check under floorboards,

Was he a yank, we call it an earth fault here? But such a fault would trip the RCD which does not seem to be happening.

but had suggested that if he is doin that, I may as well get a rewire done.

Sounds like work creation.

I haven’t noticed a pattern, the time it trips seems to be very intermittent, and frequency is up and down as well. I’ve had to move back in with parents as I can’t work from home now.

Anyone have any suggestions?

A good start would be a recording current monitor on that circuit to see what is happening. A 32amp trip is a heavy load and I would expect to see visual signs.

 

[securespark]

One wonders if the spark has done an insulation resistance test on the circuit, after unplugging everything or switching off fused connection units or disconnecting anything connected via an unswitched fused connection units.

The next step if this reading is bad is to go round and split the circuit up, testing from A to B until you find the faulty part.

It could be that the circuit in question is not on the RCD, or it could be that the RCD is faulty.

An auto test should have been done.

I have also had situations where appliances connected to the RCD have caused it to fail a ramp test, so it's important that the RCD is tested in isolation.

Did the spark do any of that?

 

[EFLImpudence]

It is an MCB that is tripping.

 

[DavidU]

Winston01 - apologies, I meant the sockets are on one circuit, instead of being split into upstairs and downstairs.

Securespark - the RCD tripping, just the MCB. Forgive me, I’m not too sure on what was done. But I can try to explain it. He tested the board and said I had a low current or amp maybe? From there, he broke up the circuit up stairs, tested again, but was finding as he described “resistance”, he found it that same resistance in my boiler flair out hence why he disconnected it. He didn’t test the RCD.

 

[securespark]

There's more that needs to be done.

The RCD needs testing to eliminate it.

The circuit needs breaking down further and testing. With any luck, there will be only one fault, which can be isolated and the rest of the circuit re-energised.if the circuit is a ring final then as a temporary measure, it can be fitted with a 20A MCB. Or, if there is space, the circuit could be made into two 20A radials.

Then the fault can be pinpointed and repaired.

 

[opps]

Why not buy an extension lead and one day run the freezer from a socket up stairs. The next day try the fridge.

Those are two appliances that cut in at random times of the day.

 

[DavidU]

Why not buy an extension lead and one day run the freezer from a socket up stairs. The next day try the fridge.

Those are two appliances that cut in at random times of the day.

Hi opps

Before I had the period of a week of no trips, it got to a point where I had everything, and I mean everything I possibly could unplugged including the fridge freezer, washer and boiler. Nothing was in. And it tripped 4 times within the hour.

 

[opps]

Hi opps

Before I had the period of a week of no trips, it got to a point where I had everything, and I mean everything I possibly could unplugged including the fridge freezer, washer and boiler. Nothing was in. And it tripped 4 times within the hour.

Fair enough.

Do you have anything else on that circuit such as a house alarm, exterior sockets/lights.

Best of luck

 

[DavidU]

Fair enough.

Do you have anything else on that circuit such as a house alarm, exterior sockets/lights.

Best of luck

No outside sockets, alarm is separate circuit and disconnected (funny enough that that’s the first time the electric tripped by the alarm going off!). The only thing I can think of on that circuit is the extractor in kitchen, but this was unplugged as well during the trip. Really weird.

 

[Wayners]

Mate had socket screwed tight causing it to bow. This caused intermittent trips.
Released it. Packed so it wasn't under stress and bent and all good.
Had another where dishwasher isolator switch had a lose live wire causing random trips.
Finally it got so bad it melted and was found.

 

[securespark]

I've got it now ...

The RCD is not tripping.

But it wouldn't hurt to test it.