Nuisance tripping RCD

Araman · Aug 9, 2011

Having installed a new cu in a customers house I found the fan assisted oven (cooker only as the hob is gas powered and the cooker was fed through the ring main) was tripping the RCD constantly. There were no faults that I could find so I laid a dedicated radial to the cooker. This has very nearly cured the problem inasmuch as the RCD now trips only once about 5 minutes after the oven is switched on and thereafter never again.
The fan comes on as soon as the oven is switched on so it is not the motor starting up that is causing the RCD to trip.

I am happy enough to lay the radial from an independent non-RCD controlled supply which will end the problem. But do any of you out there know the answer to this? Where do you think the problem is? I know I comply with 17th edition by feeding the cooker through a FCU rather than a plug and socket but it would put my mind at rest if anyone knows the answer.

Deleted member 9648 · Aug 9, 2011

Element in the oven breaking down most likely....try an IR test,if nothing shows up try it at 1000v.....(not L-N though!)

tony mc · Aug 9, 2011

As Wirepuller has stated re the element breaking down.

The only problem is if you install a new radial non RCD cct will the cable run comply with the regs.

I would suggest a new element as it sounds like its breaking down especially when cold!!!

Sounds like your final ring circuit may also have a high leakage clamp the tails and see what the reading is!!!

stott · Aug 9, 2011

It sounds tough but you can’t be held responsible for client’s crappie old oven.
If you do appliance repairs quote for repair
If you don’t inform them appliance is faulty & they should get it repaired at their cost
I would not down rate your circuit to non rcd .
I you have certificated your work & it is sound the responsibility lays with them an oven is a Portable tested bit of equipment normally classed as fixed or transportable.