What cable size would I need ??

It is impossible to complete a cable calculation and design for this circuit without actually seeing the installation.

Before calculating a cable size you need to ensure that the supply and installation are capable of taking the extra load.

Plus we all have our own ways of working and way we like things done, so if I did tell you a specific cable type, size and method of installation the electrician who does the work for you may disagree and want to do it differently.

Basically that is 50A and what cable you need would depend on a number of factors:

• The installation "method" (i.e. degree of thermal insulation)
• If it runs through a hot area
• The cable length (and so voltage drop)
• End of circuit earth fault impedance (for clearing faults fast enough to avoid appreciable shock risk)

If it were a domestic cooker then normally you apply a diversity factor as they hardly ever have everything on high at once, and the accepted practice is 10A plus 30% of the remainder = 10 + 0.3 * (50 - 10) = 22A so a 32A circuit in typically 6mm cable would do for flats and smaller homes. Typically, as the above factors need to be assessed.

But this is professional cooker and if planned for such use you would really be looking at servicing the full load of 50A and that is quite a lot more to consider.

Ah, beaten by @davesparks to the post!

pc1966 said:

Basically that is 50A and what cable you need would depend on a number of factors:

• The installation "method" (i.e. degree of thermal insulation)
• If it runs through a hot area
• The cable length (and so voltage drop)
• End of circuit earth fault impedance (for clearing faults fast enough to avoid appreciable shock risk)

If it were a domestic cooker then normally you apply a diversity factor as they hardly ever have everything on high at once, and the accepted practice is 10A plus 30% of the remainder = 10 + 0.3 * (50 - 10) = 22A so a 32A circuit in typically 6mm cable would do for flats and smaller homes. Typically, as the above factors need to be assessed.

But this is professional cooker and if planned for such use you would really be looking at servicing the full load of 50A and that is quite a lot more to consider.

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Thanks very much for the detailed reply, i will get an electrician to take a look at it I did think a 45amp trip and 10mm twin earth would cover it. It’s only for domestic use and I very much doubt it will be on full wack all the time.

Justyjust said:

Thanks very much for the detailed reply, i will get an electrician to take a look at it I did think a 45amp trip and 10mm twin earth would cover it. It’s only for domestic use and I very much doubt it will be on full wack all the time.

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The two key things are for you to decide/inform the electrician are (1) the intended use, i.e. is it for home cooking, or are you likely to use it like a professional chef (who has multiple meals and related pots / oven on the go as high/fast as possible), and (2) where it is to be located so they can look at possible cable routes and determine if they have lots of thermal insulation or not.

If domestic use then 32A / 6mm covers most cases. Otherwise 40A / 10mm, or even 50A / 16mm, might be needed along with a check on the available protection for your CU (as often 1 unit width RCBO are limited to around the 40A region) and total supply capability, etc, to make sure you are able to use that without taking out the DNO fuse should someone use an electric shower at the same time, etc.