The MCB (32a) on the ring to our upper floors (bedrooms and attic) has tripped and won't stay on for more than a short while, with nothing apparently setting it off. It did this a while ago but stopped. This morning while still in bed it went and will not stay on without tripping. I've checked all the circuits with a low voltage circuit tester but found nothing wrong.
What can be the possible reasons for an MCB tripping like this? I'm assuming no physical movement to the cables.
Antony
What make are they? I've had several Wylex 32A MCBs fail. They're fine until they trip for some reason or are switched off, after this they will latch in the On position but are electrically Off.
Dave
Maybe, but the possibility of there being an actual circuit problem (such as rodent damage to a cable, or water getting in somewhere) should certainly be investigated as there may be a significant fire risk. I would start with an insulation resistance test on the circuit in question. If you don't have the necessary test equipment get an electrician in.
You really need to disconnect all appliances and megger the cables in sections. Given the weather, and the fact that it's an attic circuit, I'd suspect dampness from some rain blown under the tiles has got into a junction box somewhere.
A lot depends on the overall state of the wiring. If there's any old rubber wiring still in use, it's shafted.
Owain
Faulty MCB
a screw through a cable plus water.
Mice.
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