MCB tripping when nothing is on!

[SparkyJan]

The MCB for my upstairs ring main keeps tripping. I have switched off all the upstairs lights including bathroom light with extractor fan and the 10A breaker still trips. This can take minutes to happen. I have siwtched the upstairs and downstairs MCBs in the distribution board and the cicuit keeps tripping so it is not a faulty MCB. What should I try next?

Jan

 

[ricicle]

A ring final circuit (ring main is incorrect) is not the same as a lighting circuit - it will supply your socket outlets. So what are you losing sockets or lights ?

 

[ELZ4742]

mcb not an rcd, right? ... have you checked the cables in the loft area?

 

[ricicle]

Edit: Just read it is a 10A breaker so it must be (hopefully) lights.

You could possibly have trouble with the wiring itself - rodent damage, water/damp ingress.

 

[Taylortwocities]

Does this 10amp breaker have a button marked "test"??

It might be an RCBO.........

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

 

[ericmark]

The 10A breaker is the bit unsure of.
Most lights have ceiling roses which are only rated at 6A so unlikely if wired correct lights will have a 10A breaker.
Ring final circuit would normally be 32A so unlikely that.
Immersion heater normally 3Kw so would need 16A breaker.
As much as I try I can't see what a 10A breaker would be used for in a house. As already pointed out it could be a MCB or a RBCO and the latter has an RCD built in so will trip with small earth fault. The RCBO will have a test button so look carefully at it.
Next is what does it control. Could it have been fitted in error? Is it even used. i.e. what stops working when it trips.
I have in the past found some one has used wrong cable and rather than completely disconnect the circuit I have fitted a smaller breaker may be this has happened with you?