oven trips RCD

[TPK1]

please help, i have just had fitted a new double oven AEG which works fine on all fronts until we try to use the main fan assisted function, at which point the rcd trips taking out everything else on same side of cu. the electrician tells me that the problem is nothing to do with his installation of new cu. or new kitchen wiring, but more likely to be a fault with the oven, any suggestions please.
oven =4.6-5.1kw wired with 6mm twe thro cooker point to 32amp breaker (radial circuit)

 

[sparkybird]

I owuld agree with your sparks. Get on to the manufacturer - the oven fan sounds faulty

SB

 

[festa]

What other circuit`s are on the RCD side in the Consumer unit?
Do you have any computer`s ,pond equipment or boiler supplied by circuit`s protected by the RCD with also protects your oven?

 

[JohnD]

yes, it is possibly a fault in the oven, though this is not common if it is new and dry. It will have been tested before leaving the factory.

However

If the RCD trips at 30mA
And you already have a leakage from other appliances of 29.9 mA
then very little (and a reasonably acceptable) leakage from the oven will push it over the edge and cause a trip. The oven is hardly to blame in that case

(in fact, background leakage always occurs to some extent, and varies from time to time, so my figures are not entirely realistic, but you get my point)

Background earth leakage most often comes from "watery" appliances like kettles, washing machines, dishwashers, coffee-makers, showers, immersion heaters, boilers and their pumps... and ovens. So try unplugging all of those and see if it makes a difference. Fixed appliances will (should) have a DP switch on the wall if they have no removable plug.

If you have had a new CU and a new kitchen circuit, the electrician could reasonably have been expected to make some tests to validate his opinion. If you call out the oven manufacturer's engineer I expect he will test the oven and may well declare it to be within acceptable limits.

What paperwork did the Electrician give you after changing the CU and installing the new circuit? Does it show test results?

Because oven always get a bit of earth leakage, especially as they age, there is a good argument for not putting them on an RCD (especially a shared one which also picks up leakage from other appliances)

p.s. can you tell us the brand name on your CU, and post a picture of it, showing the breakers? There is possibly a simple remedy.

 

[ScrewForumIsJunk]

Simple test - the oven should be connected via a CCU (a 2P device).

Isolate the cooker/oven using this CCU.

Does the RCD trip? If yes your sparky should ,have red face.

Turn on the CCU. Does the RCD trip? If yes the cooker manufacturer should have a red face.

 

[JohnD]

ScrewForumIsJunk, your test will not help if the oven has a leakage of e.g. 15mA or any number less than 30mA

 

[TPK1]

thanks for replies. to answer some raised questions the cu. is a wylex split board with each side having its own rcd apparently to satisfy incoming regs.
left side covers boiler/kitchen ring/door bell/ upstair lights/downstair lights.
right side covers upstair sockets/downstair sockets/ cooker/ shower/ + 1no spare.
i think i might try isolating shower to see if tripping still occurs ???
it does not look like cooker can be unprotected from rcd.

 

[ScrewForumIsJunk]

JohnD it will if as I said the CCU is 2P as both P and N will be isolated from the oven.

 

[JohnD]

so if the oven has a leakage of 1 mA (not unreasonable) and e.g. the washine machine has a leakage of e.g. 29mA, what will your test tell him?

 

[ceraunic_level]

Just a small point, but I think you upstairs lighting and downstairs lighting should be on different RCD's so your whole house is not plunged into darkness when an RCD trips.

 

[dingodeano]

I had same problem at a call out i attended .. i remember thinking the element was faulty , excessive earth leakage , when i actually arrived i pulled cooker out looked like a mouse had been chewing at the supply cable from DP switch to cooker !!