RCCB not resetting

Hi,

My consumer unit has an RCCB which I think protects half of the unit. The RCCB wont reset it clicks straight off even when all the MCBs are switched to off so I only have power to half of my house. Can RCCB's be faulty or is it likely to be a fault in my wiring somewhere?

Many thanks

Jane

Have you changed something recently?

Unplug all of your appliances.Switch off any others that can't be unplugged (cooker, shower etc)
It sounds like you have a neutral to earth fault, which can still cause the RCD to trip even with the MCBs off.Try reseting the RCD with all unplugged and if it resets then plug them in one by one until you find one that sends the RCD out again.
And as Crafty said have you done any alterations/DIY lately?
If you can't find an obvious cause then I suggest you employ the services of a competant electrician, recommended to you by family/friends etc