Correct cooker wiring

[jase1982]

Hello, I'm new here but would appreciate a bit of advice.

I would like to install a range belling db49ei cooker, hob is total 7.5kw, ovens are total of 4.1kw and grill is 1.8 kw. One of the ovens can be used as a grill so I calculated the maximum possible at any one time would be 14.1kw.

The handbook firstly recommends a 10 mm cable from fuse board to cooker isolator unit, then 6mm to the actual Range unit. Later, however, it says to use a 10mm cable all the way. It also says to use a 45a fuse.

The cable run from the fuse board is about 12m.

What size cable/mcb should there be in place?

 

[bhm1712]

Well going by 14.1Kw at any one time, the maximum current draw would be 61.3 amps at 230 volts, and 58.75 at 240 volts. So 45 amps is not enough if you actually plan on using the whole hob, grill and oven all at the same time...

6mm/10mm cable would not be big enough for that kind of load either.

If you really need to be using everything at once, then you need to think bigger cable and higher capacity MCB. If your house supply is only 60 amp then your pretty much exceeding that as well and if your using a washing machine or something else at the same time you would be well over.

 

[jase1982]

I thought you Might allow for diversity, hence the manufacturers recommending a 45 amp breaker? House supply is 100a. What if I use 10mm cable tccount for potential current, bite use a 45amp breaker and accept tgat it may trip out if absolutely everything is used?

 

[bhm1712]

well you are supposed to allow for diversity but the way i understood your original post it appeared as though you were wanting to use the whole lot in one go. However after re-reading i can see i was not fully awake.

If in the manufacturers manual it says use 10mm cable and 45amp MCB then do that..

 

[EFLImpudence]

Well going by 14.1Kw at any one time, the maximum current draw would be 61.3 amps at 230 volts, and 58.75 at 240 volts.

Current increases and decrease with the voltage because the resistance of the elements is the only constant.

The regulations state that the manufacturers instructions shall be followed even though diversity would result in a design current of 25A (+5A with integral socket at switch).
Hence why virtually all domestic cookers will be satisfactory on 6mm² cable and 32A mcb.

 

[Taylortwocities]

Indeed, the MI's should be followed. And they appear to be correct, for once.

Diversity is a very important part of circuit design otherwise we would all need 500amp supplies!
. Using the standard diversity rules for a cooker of 14.1KW you get a design current of around 26amps.