New Cooker Tripping RCD

[bandhits]

I bought a new kitchen inclusive of oven and hob (homark 02-700401) over a year ago and stored it a spare room until I was able to fit it.

I finally got round to putting it in a couple of months ago and tried it out, albeit very briefly and all seemed ok. Since then I have had a new Protek Supra range ip40 RCD consumer unit installed and on trying the oven thereafter the RCD tripped after about 1 minute either when on oven or grill. On resetting and trying again it came on for maybe 40 seconds and then tripped again and the cycle continued. The electrician who fitted the consumer unit told me that it would be the appliance that was at fault and to seek appliance advice.

On looking around the web i found an article which indicated that the elements may be damp and that if one were to persevere and get some heat through, on drying out the problem may be solved. I kept on trying to no avail, then unwired the cooker from the mains and connected it instead to a normal extension lead and plugged the cooker on via a socket on another circuit. With perseverence the cooker and the oven both eventually came on and stayed on for 20 mins or so until switched off. I then connected the cooker back to its original circuit on the cooker rcd and found myself back at square one....tripping immediately. I disconnected it again and put it back on the extension lead, plugged it in a normal wall socket again, which worked fine before and this time it just started tripping again.

A mate of mine took the cooker to his house (non RCD) and it blew his fuse immediately. Up until this point I felt sure the fault must have been with the consumer unit as opposed to the cooker itself. I really would appreciate any advice that any one can offer.

I rang a few appliance repairers and most say the elements have gone, but if this were the case then why did it work so well for the period I had it on?

 

[sparkiedave]

If you've moved the cooker around a bit you may have damaged it internally somewhere, if it's tripping the RCD every time, you could get a spark to carry out an insulation resistance tests between Neutral and earth, then between live and earth if it's popped a fuse in the past, also might be worth getting the RCD and cooker circuit tested too

 

[electronicsuk]

Can't find a lot of information about this oven, so I assume it's pretty old. The only little bit of information I did glean is that it's a double oven. If that's true, then it very likely isn't designed to be run from a 13A plug, so I'd suggest you don't try that again.

I also suspect that Homark may be a rather cheap and cheerful brand, on account that I haven't heard of them before and can't find a lot about them. On that basis, coupled with the fact that it didn't work at your friend's house either, I'd be inclined to think that the oven has had it.

If the RCD in the new consumer unit has been tripping almost instantly every time you try to use the oven, I'd suggest that the neutrals for that circuit had been wired incorrectly. However, that doesn't seem to be the case here. It would be worth checking that all connections are tight, especially the neutrals, but it could be that the cooker fault is simply a coincidence. Either that, or your electrician has somehow damaged it during IR testing. After all, he did install a Protek consumer unit...

 

[ericmark]

As already stated internet search only brings up spare parts. However with the exception of induction hobs most cookers used the same types of element. And in general no single element is over 3000W so you should be able to run a single element from an extension lead.

There are though a few questions that come to mind.
1) One would assume if main cooker supply is through a RCD so would any 13A socket so if there is a fault with the cooker taking out a RCD running off a 13A socket should also take out the RCD unless you never connected earth which would be rather dangerous.
2) If it blows a fuse with a single item used then we are not looking at damp and some where there must be a short circuit.

This raises another question:- Was the cooker new? If not it would seem likely one of the elements has blown and this is causing the short circuit and since most controls only work on the line as current is drawn it will trip out the RCD with a neutral earth fault hence why two circuits affected.

If it is new then likely moving it around has disturbed something causing a short circuit plus the original damp problem.

You are right elements are hygroscopic and tend to absorb moisture from the air and once heated up once they tend to be OK again unless left for long periods unused. However it is obvious there is something else wrong here. The hygroscopic problem does not cause fuses to blow. Cookers do not use rocket science and are relatively easy to repair but it does require some test equipment to work out what is wrong so you need an electrician of some type to find out what is wrong with it. Quick look on the net shows cookers starting at around the £150 mark and as such it could easy work out more expensive to repair than to renew with elements costing between £14 and £33 couple of elements plus labour could easy exceed price of new cooker.