Started with the cooker tripping the MCB

[TheHandyAndy]

Hi all,

Not being a very good week for me so far!

Tonight, I was cooking on the gas hob on my Cannon C60DTC cooker, no problems there. Then a very loud pop and a tripped MCB, not the RCD. I have a brand new CU installed and fully certified to 17th eddition.

Anyway, as the oven wasn't even on I reset the MCB which then caused the RCD to trip.

The cooker is on it's own circuit with nothing else on the same supply. I've tested the cooker isolation switch on the wall, no problem there, I've also had a look at the connection on the back of the cooker there either. I thought that it might be a dodgy oven element, but the ovens or grill weren't in use.

Any ideas? The gas supply is still ok, so at least I can use the hob, but not having an oven or grill is somewhat a pain in the rear!

Thanks in advance!

 

[riveralt]

With the Dual pole cooker isolation switch off does the MCB reset?
Does the ignition for the gas come from the same circuit?

 

[TheHandyAndy]

With the Dual pole cooker isolation switch off does the MCB reset?
Does the ignition for the gas come from the same circuit?

Hi Riveralt!

Yeah, when I turn off the dual pole switch, the MCB reset no problem. When I then turned on the switch to the cooker, the RCD tripped and continues to do so. The MCB doesn't trip any more. I disconnected the connection at the back of the cooker to check if there was a wiring problem, with the cooker disconnected and the switch turned on, everything is fine. Cooker is definetly at fault, but as the ovens or grill are switched off I'm guessing it's not the elements.

How can I find out about the gas igniters? I think using logic they are probably at fault, but how to check?

 

[Taylortwocities]

An RCD will trip if there is a fault on the live or the neutral leg. The switch in most appliances is in the live leg but that leaves the neutral still connected to the RCD.

So the cooker would appear to have a fault. Time to call in a repair man, unless you feel able to do some fault-finding.

 

[TheHandyAndy]

Got to the bottom of it today!!

Stripped it down and checked all wiring. Found that 2 wires under the hob were touching the underside of the hob, resulting in them melting together and shorting out the main circuit board!! So I've repaired these by cutting out the wires all together as they are ones that run from the main board to a diagnostic socket on the back of the cooker. There was a rather good black sooty spot about an inch or so across and some of the tracks on the board burnt off.

Since the burnt out wires have been removed, I can now switch on the cooker without it tripping the CU. Although I'm not actually going to leave it powered up.

Anyway, Ransom Spares had a new board in stock. So wait for that to be delivered and will put it in.

Thanks for the suggestions guys.

Andy.