Cooker power supply rating and cable

Cooker power supply rating and cable

Author
Discussion

Robertb

Original Poster:

2,721 posts

253 months

Thursday 4th July 2024
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We have a new Rangemaster dual fuel twin oven range cooker which we bought to replace a gas one which had croaked, as we liked the idea of fan-ovens.

The gas installer couldn’t proceed as he was not sure the power supply was of the correct size for the 11kw potential all-on consumption so asked us to get an electrician involved.

I’ve scoured the net and there are conflicting conclusions… some say for 11kw you’d need 10mm cable, others say 6mm (which we have) is sufficient.

The electrician who came thinks we need 10mm but is happy to be led by other reliable evidence as curiously Rangemaster themselves say 6mm is fine in their FAQ for an induction or ceramic hob model (which would presumably draw more power than a gas hob), but aren’t specific on which exact model.

Upgrading to 10mm would be disruptive so we would just swap the cooker for a gas one, but thought I’d canvass some views before doing so.

Any thoughts gratefully received!

Mercdriver

3,000 posts

48 months

Thursday 4th July 2024
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When in doubt go higher, even a sparkie is not sure, I would not risk it

thebraketester

15,007 posts

153 months

Friday 5th July 2024
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11kw is 46amps @240v. Look up cable rating.

Belle427

10,535 posts

248 months

Friday 5th July 2024
quotequote all
Have a look here to give you an idea.
https://www.tlc-direct.co.uk/Technical/Charts/Volt...

Sheepshanks

37,041 posts

134 months

Friday 5th July 2024
quotequote all
it’s allowed to use diversity for a cooker - it’s assumed everything wouldn’t be on at the same time.

Ie: https://www.tlcdirect.co.uk/Book/6.5.2.htm#:~:text...

but that article explains why you might want to think about it a bit more.

journeymanpro

859 posts

92 months

Friday 5th July 2024
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Your electrician not heard of diversity?

Robertb

Original Poster:

2,721 posts

253 months

Friday 5th July 2024
quotequote all
Thanks very much folks, useful info to research further there.

Diversity is a whole new world for me (aside from the dance group or section in our company’s HR manual), will see what the electrician has to say.

Mine is a Rangemaster 110 Professional Deluxe which has a max electrical load of 11kw but it’s hard to imagine using everything at once.

Mr Pointy

12,534 posts

174 months

Friday 5th July 2024
quotequote all
If your electrician didn't know about diversity calculations then get a proper one who knows what he is doing.

eliot

11,882 posts

269 months

Friday 5th July 2024
quotequote all
you could put it on a 32a breaker which would protect the 6mm cable. If it keeps popping, then clearly you need a bigger breaker and therefore thicker cable.

How long is the run from the consumer unit to the cooker - sometimes you need to go up a size if it’s long.

Mr Pointy

12,534 posts

174 months

Friday 5th July 2024
quotequote all
Robertb said:
Thanks very much folks, useful info to research further there.

Diversity is a whole new world for me (aside from the dance group or section in our company’s HR manual), will see what the electrician has to say.

Mine is a Rangemaster 110 Professional Deluxe which has a max electrical load of 11kw but it’s hard to imagine using everything at once.
From the online manual the induction version has a load of around 15.35 kW (excluding induction boost use) so the nominal braker rating would be 30A (10+ (0.3x(15350/230)) assuming no auxillary socket on the cooker outlet. However with such a large range a 40A breaker at least would be more sensible to avoid tears on Christmas Day.

Whether the cable needs to be 6mm or 10mm depends on the run length & how the cable is fixed & only your sparky can calculate that.

Rough101

2,698 posts

90 months

Friday 5th July 2024
quotequote all
If your electrician knows the load and route, but can’t work a size out, he is incompetent.

The manufacturer can’t tell you the cable size, other than the final connection capacity, as they don’t know the cable installation method, the protective device rating or the distance to the switch/ connector.

Edited by Rough101 on Friday 5th July 10:49


Edited by Rough101 on Friday 5th July 10:59

JimM169

690 posts

137 months

Friday 5th July 2024
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Mr Pointy said:
If your electrician didn't know about diversity calculations then get a proper one who knows what he is doing.
This^^^^^

I'd also be questioning any other work he might have done in your house!