electric cooker problem

[Voodooguy]

I have a 10kw dual oven electric cooker. It was installed by a qualified electrician about 10 years ago, who used the existing 6mm cable (over insulation, through the loft space) and upgraded the MCB to a 40A. I have a safety certificate for the work. The consumer unit and the wiring for the cooker circuit was installed in 2007 by my landlord.

Earlier this year, I had new electric storage heaters and electric boiler installed by the landlord, along with a brand new consumer unit. However, not long after this installation, my cooker started acting up. Not immediately, but within a couple of weeks. First the top oven (with the grill) went, so I started using the bottom oven and lived without a grill. But now the bottom oven has packed up too. The other night while it was turned on (only the oven was on, no hobs), it tripped the MCB (and all of the other things on the same RCD group). Although I could just switch it back on again, the oven will now no longer heat up. The fan works perfectly, and the heating/themo light comes on, but no heat. The hobs still work fine (for now).

I've noticed that the new consumer unit I had installed this year now only has a 32A MCB for the cooker circuit rather than the 40A that my own electrician installed. I'm wondering if this is somehow responsible for the cooker problems. Any ideas?

 

[Geoff1946]

Sounds to me like the elements in your cooker are coming to the end of their lives.

 

[BorisJ]

The 32 amp MCB is correct. Due to diversity the cooker will never use 10kW.

The 15 year old cooker problems are probably due to age and it is a coincidence that it has happened now.

 

[Voodooguy]

If it was just one oven packing in, I'd be inclined to think it was just the age of the cooker (which is about 10 yrs old, its the old consumer unit which was 15). But it was the top oven and the grill which packed up a few months ago (same space but different heating elements, which suggested an internal fuse or thermostat issue to me). The bottom oven, which is the fan assisted one, I rarely used in the time I've had the cooker, but I have done maybe half a dozen times this year since the top oven stopped working. And now that's packed up too. The bottom oven is what tripped the rcd the other night, even though it's only 2.5kw and was the only thing switched on at the time. I can't believe the heating elements in the bottom oven have had their day because it's hardly been used.

The cooker's manual states it should be connected with a 45A mcb and 10mm cable, though my electrician stated that would only be necessary if both ovens and all the hob rings were on simultaneously and based on how the cabling was installed. The unlikelihood I would ever have the cooker turned on to full capacity, he opted for a 40A mcb, for which the current 6mm cabling was fine. It ran fine all these years, not tripping once. Until the new consumer unit and 32A mcb was installed this year. It's possible it is just a coincidence, but it seems a pretty big one to have both ovens - one of which was barely used - go within months of each other. And not long after the new consumer unit and lower mcb were installed.

 

[Geoff1946]

Elements can deteriorate even when not used. The mineral insulation often takes in atmospheric moisture which compromises the insulation.
If your cooker is in otherwise good order it may be worth having an appliance repair specialist quote to replace the oven elements.

 

[Voodooguy]

I'm waiting for a couple of quotes but wondering if its just worth buying a new cooker instead (a like for like, but better brand, is about £350, but maybe cheaper with Black Friday around the corner).

Was just reading another thread ("Rcd trips when oven reaches temp...") which seems to be a similar problem.

 

[BorisJ]

There is no way changing the MCB will cause the oven to fail.

The manufactures instructions are wrong saying use a 45a MCB. (Not for the first time, they are written by marketing people not engineers). The 32 a MCB is correct and the cable could even be 4mm.

 

[ProDave]

If you are a tenant, you don't even need to waste energy trying to understand what has gone wrong. Just report to your landlord that your oven does not work and he should arrange to repair or replace it.

 

[Voodooguy]

If you are a tenant, you don't even need to waste energy trying to understand what has gone wrong. Just report to your landlord that your oven does not work and he should arrange to repair or replace it.

The cooker (along with every other appliance in my home) is my own property and I am responsible for any repairs to it. But if it was a problem with the consumer unit or wiring, then it's the landlord's responsibility. Hence the reason why I posted in the first place.

 

[ProDave]

Well if the lights and fan on the oven work but it does not heat up, then it is an element, switch or thermostat issue, i.e. a fault inside the oven, and if it is yours you must repair it or replace it.

 

[Voodooguy]

Yes, already aware of that.