Wondering if there's an easy solution to this one???

I have just replaced a Diplomat single cavity 90cm range cooker with a Brittania double cavity 90cm range cooker.  The new oven powers on fine, and grill elements work etc.

When I put on the larger of the two ovens, and wait until the oven reaches required temperature, the oven will 'trip' the RCD on the consumer board and ALL electrical items go off in the house.  The trip switch for the oven does not trip out - the only one is the main RCD.

The main RCD is a 30A rated one, which has been suggested to me is not enough for the new oven, or even that it is possible that it has degraded over time so as not offering the full 30A throughput.

Any ideas anyone? - many thanks in advance.....

Any chance of a picture of the RCD?.. reason is there are several different types!

What rating is the MCB/breaker for the cooker circuit in the consumer unit?

When the oven is on and the RCD trips, is there anything else on (on the range)?
Have you tried turning the oven on and not using anything else, like toasters, kettles, immersion heaters etc?

I can see 3 potential problems:
- the range draws a lot of power and it may be overloading the 80A RCD causing it to trip. Without knowing what circuits are being fed from where etc it is difficult to work out the total load on the RCD. It could be the range + the kettle + a few other smaller things running at the same time = overload.

- there may be a fault on the range that is causing the RCD to trip, I don't think this is the case because I suspect it would trip sooner.

- I can't remember what the 3rd one was, I need to go to bed... Ah yes the RCD could be over sensitive or faulty.

It depends on the rating of your supply. Most domestic properties either have a 60A, 80A or 100A supply, normally the main fuse should be labelled (sometimes the fuse carrier says 100A but the supply company may have put a smaller fuse in at some stage). If yours is a 60A or 80A then you may be limited. If you have a 100A supply then you could look at replacing your CU with a 17th edition version, then separate the circuits so you don't have all of the big loads going though the 1 RCD.
There is diversity to factor into the equation and a number of other things which are difficult to do remotely.

Ideally I would like to check the current (A) with a tong tester (clamp meter) on the the RCD, to make sure it is not tripping prematurely (it does sound like it is). If the RCD is faulty then you can replace it with a similar RCD, I would not put one with a higher rating in because you run the risk of overheating cables and things not tripping soon enough: read fire! You could get a clamp meter off eBay or from Maplins to check the current being drawn by the range and immersion, to see if it is enough to trip the RCD.
All this has to be done live so at your own risk and it is best to be done by a competent person!!

Quote:

Still waiting for the picture that LSpark asked for to confirm...

Yes sadly RCD's don't cut-out under overload conditions, they burn out.. eventualy. But it's going to take more than 13kW oven to do that.

But the main question here is WHAT devices the gentleman has, no one here knows, so any advice is really premature. Even a picture won't be 100% conclusive, but it would give us a much better idea than guessing and going on maybe's!

Who's crawling where?!.. there's to be no babies in the forum please, this isnt kindergarten  

Your quite right Zamb, there is way too much technical talk, but at the end of the day it's a technical "scientific" type subject. Unfortantely it doesn't matter how much you simplifiy it sometimes it doesn't make much difference.

As you point out, some people don't know the difference between fuse boards and CU's, plugs and sockets, fuses and circuitbreakers. But it does make a big difference as we all know, different jobs for different devices performing different tasks.

That's why it helps all of us if a picture is available, speaks more than words, of-course it's always best to call an electrician in if someone is having difficuilty, un-like plumbers (sorry guys!), it shouldn't cost the earth to have someone check it out. In greater london I would charge £45.00 (no vat) and should be able to diagnosis most problems with equipment at hand in less than one-hour.

Now please, get out from under MY rock Z, I'm just not prepared to share it right now, times are hard  

LSpark wrote on Apr 17^th, 2009, 3:07am:



!!!!!!!!!!! are you polski?

I think he is trying to say you are undercharging