2 x Ovens and a hob - can anyone help?

[Tattyt]

Hi,

I have had an electrician out to look at at what needs to be done to install two new ovens and a new hob.

Existing: 6mm cable which was used for a double oven & hob previously, with one isolating switch. 40A breaker (think it should be 32A)

Two new ovens: Neff 2 x 2.99KW 13A
New hob: 6.5 KW

I just want to confirm that his recommendations are correct as it involves running some new cables so carpet, floor boards up etc etc.

If anyone could advise that would be brilliant

 

[Wilko]

I've not had problems following the 6mm 32A approach myself, but I've one to do that's given me pause for thought. Biggest fully electric range (for household use) I've seen and says 14.5kW on specs. I thought, I know - I'll check with their tech department. They emailed advice of 45A OCPD and RCBO as it has 8mA leakage. . I felt like asking if that would improve if I cooked the elements for a while, but chickened out.

 

[EalingBadger]

14.5KW on a 45A OCPD?

Diversity is one thing, but surely there must be a (considerably) greater than zero chance of everything being turned on all at once from time to time?

One only has to imagine Christmas dinner with a few of the relis to see how.

Even though the oven with the bird and the pigs-in-blankets in it will likely be up to temperature and thus only clicking in and out relatively infrequently as the crisis peak approaches just before the critical moment when dinner is ready to be served there are still going to be times when this will happen when you have the plates, stuffing, parsnips, beef (for those weirdos in the family that don't like turkey), and the roasties keeping warm in the second oven, and then the hob rings are being used to cook the carrots, peas (for those weirdos in the family that don't like mushy peas), sprouts (which have been on since the 1st of November just to make sure that they are properly cooked), mushy peas, cauliflower cheese (my sister-in-law does a stunning Christmas lunch but this is just plain weird of her), whilst the bread sauce (s-i-l weirdness again! ) and Xmas pud are slowly simmering away at the back.

I mean surely, this has got to test the endurance of the poor old 45A OCPD hasn't it?

 

[MFS Electrical]

just as an aside, i recently came across an installation where a 6.0mm cable on a 30A 3036 fuse had happily been supplying a sub-main feeding a free standing cooker and a 8.5kW shower. been fine for over 30 years. no sign of cable damage.

I’ve seen that before shower piggy backed from cooker switch how the hell they fitted two 6mms in I’ll never know none of them even had cores chopped to fit I got the call because the cooker isolator smelled like fish when the shower was on

 

[freddo]

A problem with many newer cooking appliances is that the instructions demand a maximum fuse/MCB rating of 16A or 20A.

 

[FatAlan]

14.5KW on a 45A OCPD?

Diversity is one thing, but surely there must be a (considerably) greater than zero chance of everything being turned on all at once from time to time?

One only has to imagine Christmas dinner with a few of the relis to see how.

Even though the oven with the bird and the pigs-in-blankets in it will likely be up to temperature and thus only clicking in and out relatively infrequently as the crisis peak approaches just before the critical moment when dinner is ready to be served there are still going to be times when this will happen when you have the plates, stuffing, parsnips, beef (for those weirdos in the family that don't like turkey), and the roasties keeping warm in the second oven, and then the hob rings are being used to cook the carrots, peas (for those weirdos in the family that don't like mushy peas), sprouts (which have been on since the 1st of November just to make sure that they are properly cooked), mushy peas, cauliflower cheese (my sister-in-law does a stunning Christmas lunch but this is just plain weird of her), whilst the bread sauce (s-i-l weirdness again! ) and Xmas pud are slowly simmering away at the back.

I mean surely, this has got to test the endurance of the poor old 45A OCPD hasn't it?

Especially with two lots of mushy peas

 

[Wilko]

The Tech Person stated 45A was their advised minimum OCPD rating after diversity was taken into account. I'm quoting for 10mm and 50A rcbo and fittings. I'll report back with max current and leakage and we'll see if the Customer's money was well spent. But that may not be till January the speed these guys are moving.