MCB Tripping

[D12DNA]

Hi there, hopefully someone can help.

Our house purchased from new in 2006 has developed a problem with the electrics. Every now and again the MCB for the garage on the main fuse board trips for no apparent reason (the last time in the early hours of the morning). There is a separate fuse box in the garage which has two circuits (one with a double socket, with fridge freezer and tumble plugged in & the other with an internal light and an external security light). Previously after approximately 1 week all seems to settle down, the MCB can be switched back on a all works fine for 6months or so, however this time even with turning of the main fuse switch in the garage, the MCB will not reset.
Apologies if a bit long winded but hopefully you are able to help.

 

[LearningSpark]

Is it definately an MCB which is tripping? not an RCD or RCBO?

 

[Taylortwocities]

Are you sure that is an RCD and not an RCBO or an RCD?

Tell us exactly what is written on the device. Also, here is a handy guide:

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• Taylortwocities
• 27 Mar 2010
• 43

 

[flyingsparks]

If the MCB is still tripping with the main switch on the garage DB off, then it would appear you have a fault on the supply cable from the house DB to the Garage DB. Are you sure its only the garage on this MCB? Check for any obvious damage from vermin, or water ingress at a junction box possible if there is any (I would hope there isn't!) Sounds like you need a spark with some test equipment to find out where the fault is..

 

[D12DNA]

Thanks for the prompt response, i believe its the MCB that tripping, see attached photo

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• D12DNA
• 8 Feb 2011
• 1

(hopefully!!) wording on the MCB is Hager, MTN120, B20. The house as 4 1/2 years old so would still be covered under the NHBC, if that would be of any use?
Thanks.

 

[ban-all-sheds]

The house as 4 1/2 years old so would still be covered under the NHBC, if that would be of any use?

None.

The guarantee is about as much use as a kleenex condom for things going wrong the day you move in. I know it doesn't cover plumbing after 2 years. An electrical fault 4-5 years down the line? I doubt it.