Strange mcb trip scenario..

[david1805]

Morning all,

A colleague of mine has just asked me to consider a problem she is apparently experiencing. I will have a proper look later but for now will give the brief facts as they were given to me in case anyone can suggest the cause.
My colleague found this morning that her fridge / freezer was off and subsequently found that the mcb for the kitchen sockets had tripped out and wouldn't reset. For whatever reason she switched off the adjacent mcb (the sockets for the rest of the house) and then found that the kitchen mcb reset ok. If she then reset the other mcb the kitchen would trip out, so for now she has left the kitchen mcb on but has no power to the sockets in the remainder of the house. As I say I will have a look for myself later as I'm not sure the facts stack up but for now any ideas anyone? Would a loose neutral connection cause this kind of problem?

Thanks,
David.

 

[timtheenchanter]

I would suggest unplugging everything then try to re-set both MCB, if it stays on OK, plug in items one by one till it trips, then you will have the culprit.

If not it may take a bit more detective work.

 

[Softus]

You need facts.

It could be that the lady is saying "MCB" when she should be saying "RCD" or "RCBO".

If she really does have the situation where turning on one circuit causes overcurrent in another, then clearly the circuits are not independent, either because of a faulty installation or by damaged cable somewhere.

Both of those are extremely dangerous scenarios.