Type of wire needed for Oven and Microwave oven

60BOWENS

Hi

What type of electric wire is needed for in built Oven and Microwave oven.

We dont wish to get into circuit problems,appliance breakdowns or trippings.

Two sparkies we got to get the work done said any type of wires would do.However previously wheneven we got microwave and oven on at same time,we used to get frequent circuit breaker tripping.

Many Thanks

FreeBear

Assume a 3KW oven, and a 1000w microwave (which will be around 1.5KW input power), you'll be drawing a maximum of ~19A. Problem with a microwave is it has a ruddy great transformer inside which has a very high startup load which could be causing your MCB to trip. A type C MCB should solve any nuisance tripping when turning the microwave on. Changing the wiring isn't going to fix the problem on its own.

What rating of MCB (and type) do you currently have fitted ?

FaceHead

Is it the MCB or the RCD that trips. That is the breaker that protects just that circuit, or one that has other things on it too (e.g. upstairs lights)

Well it's simply not the case that "any type of wire will do". What are the ratings of the appliances? (Freebear provides some sensible guesses, but let's hear what the appliances you've chosen actually are).

Is anything else going on that circuit too? e.g. Other built in appliances.

Realistically you'll need a 32A ring in 2.5mm twin and earth. It would be able to take another couple of appliances too.

Ectophile

What sort of electrician would say "any type of wires would do"?  That's just asking for trouble.  You need to look at the rating plate of the oven, at least.

A single oven will often take 3kW, and can have a 13A plug on it.  Double ovens need more, maybe 16A or 20A.

Then, what sort of circuit - a ring or a radial?  Both on the same circuit, or a separate radial for each?  The answer could come out anything between 1.5mm² up to 4mm².  Whatever cable you use has to be adequately protected by the breaker at the consumer unit.

Risteard

FreeBear said:

Assume a 3KW oven, and a 1000w microwave (which will be around 1.5KW input power), you'll be drawing a maximum of ~19A. Problem with a microwave is it has a ruddy great transformer inside which has a very high startup load which could be causing your MCB to trip. A type C MCB should solve any nuisance tripping when turning the microwave on. Changing the wiring isn't going to fix the problem on its own.

What rating of MCB (and type) do you currently have fitted ?

There shouldn't be any huge inrush current from a microwave. There is absolutely no reason not to use a Type B circuit breaker. These should never simply be replaced with Type C or Type D devices either, without understanding the effect this has on the maximum Earth fault loop impedance permitted to cause operation within the required times.