mcb still on?

[mikeywright]

I am having the same problem (ie. I can physically reset the MCB in that the switch stays 'up' but no power is restored). I assume the MCB is broken.

How do I replace? CU is a Memera 2000 but I looked on their website and no manual is available for download.

Thanks,
Mike
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Moderator

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[andy]

For safetys sake I'd replace the MCB.

I am having the same problem (ie. I can physically reset the MCB in that the switch stays 'up' but no power is restored). I assume the MCB is broken.

How do I replace? CU is a Memera 2000 but I looked on their website and no manual is available for download.

Thanks,
Mike

isolate CU before removing cover, and remember, if you switch off from the CU isolator, there are still live parts inside

to replace, remove cover and losen screw at top and bottom, remove the cable for the circuit and remove the MCB. itll either slide upwards or youll need a screwdriver to release it from the lever at the back. do this in reverse to add the new MCB

 

[mikeywright]

Thanks for the quick reply, sounds like a job for a sparky to me!

 

[Lectrician]

Very rare for this make of MCB to go squit. Probably a fault somewhere.

The more recent memera boards may need the busbar removing to take the MCB out - It depends if the spark who fitted the CU used the small busbar spacers supplied - many don't know what they are for and bin them.

Also, what quiet often happens, is the busbar sits on the wrong side of the 'vice like' terminal, and sits with casual contact. A little knock and it stops working. With lights it could sit like it with out realising, a higher loaded circuit would usually buzz and ark a lot.

 

[mikeywright]

Ok I was feeling brave (and tight) so decided to do it myself. I got the suspect MCB out from the upstairs lighting circuit and swapped it on to the downstairs lighting circuit. Hurrah - it didn't work, so definitely a fault on the MCB. Then swapped it back and put the power back on.

With hindsight, I guess I should have tried the working MCB from downstairs circuit on the upstairs ring, just to make sure there isn't a line fault, but then it seems v.unlikely that the MCB and the line would develop a fault at the same time.

Off I went to the shops to get a new one. But, of course they don't stock the brand I need in B&Q or Wickes, so I'll have to wait until AC electrical opens tomorrow.

In conclusion - it might be rare for them to fail but that doesn't mean it never happens (as someone said before)!