MK 12 Way Consumer Unit Keeps tripping

[JonKing]

Laying in bed 12:30pm I noticed my Wireless router was knocked out. Came down stairs and checked the consumer unit and it had tripped. Re-set it and all was OK went back to bed. Unusual not happened before. Next day 11am it tripped again. At this point I became suspicious. Before re-setting I turned every switch off, re-set the consumer unit and then turned the switches on in turn. Isolated the problem to the kitchen circuit. I unplugged every appliance in the kitchen and turned off every plug. I then tried to switch it back on. It tripped again and would not turn on. Since there is nothing drawing power but the switch is tripping, and nothing has happened in the property I am suspicious there is a fault with the MK 12 way unit? But why would this just happen now? The consumer unit was fitted (new) on 3/8/2011 (marked on the unit). I moved into the property in 2/1012. I have tried everything I can think off - but suspect I need a spark to run some fault tests on the wires? Is this the next step for me? I have specifically joined this forum because of similar posts and found the quality of the advice to be top notch! Here's hoping for some more....

 

[Richard Burns]

I would say that you have a fault in (possibly) your kitchen circuit. This could be water ingress, loose cable, worn cable, all sorts of possibilities, but as you say I think you are now at the requiring an electrician to test the installation.

If you tell him what you have done, this may assist him to narrow down the fault.

 

[Octopus]

Where are you in Surrey? Sounds like you've got a fault.

 

[Marvo]

Moved to DIY forum.

 

[Edd]

Sounds like a L-E fault on the kitchen circuit, so with the MCB off everything else works. If it was a N-E fault even though the MCB was off the N and E are still conected and loading the other circuits would inbalance the RCD through the N-E fault.
If you have indeed unpluged everything from the circuit including extention leads etc then you do require someone to split the ring down and do an Insulation resistance test across the circuit to locate the fault.

 

[Des 56]

Are you absolutely definite that there is nothing whatsoever plugged into the kitchen ring

A reminder for perhaps a cooker hood,under worktop appliances,external light,fridge or freezer,washer, under cupbaord lights etc
You did mention that you unplugged the appliances,some peoples mistake is to just switch off at the socket
With a single pole socket,the fault may then be still connected to the circuit through the neutral,the same applies to some switched fused spurs,they could be single pole switched,this is unlikely but its worth a thought

Also worth unplugging appliances throughout the property that are sharing the same Rcd

 

[dcelectrical]

think about what time it trips
do you have a boiler ? where is that plugged in
failing that the fridge and freezer and the next candidates

 

[JonKing]

Sounds like a L-E fault on the kitchen circuit, so with the MCB off everything else works. If it was a N-E fault even though the MCB was off the N and E are still conected and loading the other circuits would inbalance the RCD through the N-E fault.
If you have indeed unpluged everything from the circuit including extention leads etc then you do require someone to split the ring down and do an Insulation resistance test across the circuit to locate the fault.

If I need an electrician to conduct this test, can you offer any advice on how I should establish they are qualified to conduct the test? For example should they have certifications and the type of work involved? It's always useful to have this to help qualify their suitability? Thanks in advance

 

[JonKing]

Thanks dcelectrical for your reply. On the RCB board every switch is ON except the 'Kitchen Sockets'. In the kitchen EVERY Plug is OFF and NOTHING plugged in (i.e. there are no appliances drawing power). When I turn the switch on the RCB for 'Kitchen Sockets', the unit instantly trips. So IMO it is a problem with the Kitchen ring main.

 

[JonKing]

Verified NOTHING plugged in. Tried unplugging all appliances-but no difference.

 

[Octopus]

Initial tests would be to test the RCD and the insulation resistance of the circuit you believe the issue to be on.... however as the RCD is covering a number of circuits it may be necessary to IR test all these circuits

With respect to identifying "who" is capable, unfortunately possession of a few exams and pieces of paper aren't always a guarantee of experience - so best ask you neighbours and close friends.

 

[JonKing]

Thanks for the solid advice - it helps me to understand the language if nothing else! Will let you know how I get on.

 

[HandySparks]

Whereabouts in Surrey are you?

I quite enjoy fault finding, although the main problem is being unable to give the customer an estimate on how long the job's going to take. If you're lucky, it may only be an hour or so; if not, it could easily be several hours, especially if the fault's intermittent.

Qualifications are good, but experience and having "a nose for the job" is more important.

 

[Kate]

Fault finding is a whole new ball game. This is where experience out weighs qualifications

 

[Octopus]

Me thinks the OP was hoping we could tell him how to do it himself.

Kate - I quite agree, to be good at fault finding you needs to have found lots of different faults!