Hi,

We just had what we thought was a power cut. All the electrics cut out, until we realised it was the main circuit breaker which had tripped. None of the individual circuit breakers had tripped, just the main.

I turned them all off again, flipped the main breaker on, and then one by one switched the circuits on. The main breaker tripped when the circuit marked 'upstairs lights' was switched on, indicating a fault with that circuit.

This has happened once about 2 years ago, when terrible stormy weather caused a leak which passed through one of our loft extension light sockets and tripped that circuit. The problem stopped when the weather stopped and the light dried out and we've never had such bad weather again. This time, we have not had any significant rain or wind for days.

But what we have had, is really, really cold weather (-7 at night). Our car doors have been frozen shut, the outside tap is frozen inside, that sort of thing. I mean, it's warming up during this afternoon, but could the cold weather have caused this?

Or could it more likely be something else?

Thanks
iddqd2003

Could very well be condensation.  Give us some context, type and age of house etc.

 

Switches and sockets on outside walls of cold uninsulated brick or stone walls can be prone to condensation in very cold weather.

45 minutes ago, ProDave said:

Could very well be condensation.  Give us some context, type and age of house etc.

 

Switches and sockets on outside walls of cold uninsulated brick or stone walls can be prone to condensation in very cold weather.

It’s a 1990’s house, no external sockets, but we did just get an outside light fit…

9 minutes ago, zaarin_2003 said:

It’s a 1990’s house, no external sockets, but we did just get an outside light fit…

ALWAYS look at the recent alterations first.

 

That is always one of my questions "have you had ANY work done recently"  It's a shame not everyone answers that properly, it could save them a lot of time.

1 hour ago, ProDave said:

ALWAYS look at the recent alterations first.

 

That is always one of my questions "have you had ANY work done recently"  It's a shame not everyone answers that properly, it could save them a lot of time.

I feel a bit told off, but to be fair you didn’t ask me that!

 

I checked and the new light is on a different circuit to the upstairs lights circuit that is being tripped.

29 minutes ago, zaarin_2003 said:

I checked and the new light is on a different circuit to the upstairs lights circuit that is being tripped.

Earth leakage faults are funny things, particularly if they create a path between neutral and earth.  The imbalance is not enough to trip the RCD until you draw a substantial current, which is why turning on a different circuit may have been the one that caused the RCD to trip, but not the circuit that actually has the fault.