Cooker supply 12kw correct cable size

Adamk · Dec 17, 2017

Hey guys

I’ve run a 6mm for a cooker, runs about 10metres. The customers has changed her mind on the cooker and gone for a 12kw range. Went back today to finish off and saw this lovely surprise. I know you have to take diversity into account. But for my peace of mind. Would 6mm 32a MCB be fine?

Kind of panicking a bit as the jobs finished.

What you think? Please dont tell me to tell her to change it as that’s not really an option

Thanks

Adamk · Dec 17, 2017

mattg4321 said:
If you use diversity then 17.7kw cooker comes out around 30A so in general 6mm2 is going to be fine imo.

True, but you charge the customer the extra money for the bigger size cable and it’s no real difference running it in. Even though it comes out at 30a I’d say you were pushing the boundaries. Nothing wrong with what your saying, just rather chuck a 10mm in. If I would of known my customer was putting in 12kw cooker (hense my original post) I would of put a 10mm in.... peace of mind I guess

Midwest · Dec 18, 2017

We've just had a new 'range' style cooker installed, primarily 'cos the old one was rubbish, and the door wouldn't close.

The old one was about 2.2kW (total), and connected with the manufacturers 1.5mm flex to a 10mm 45amp supply. I chose the install/disposal method 'cos it had gas hobs, and they can hump old & new about.

The new one has a total load of 8.6kW, and you can have all elements on at the same time. Now I was quite comfortable with the old set up, and would of been happy connecting new oven to 6mm 32amp supply.

Come installation day, engineer commented old connection was wrong, and he had to check I had a 10mm 40amp supply for the new one. He also used a bit of 10mm tw&e from cooker outlet to oven.

I've been meaning to clamp the thing on start up, just to see how many amps its pulling and for how long. But, somehow I don't think 6mm would of been a problem.

telectrix · Dec 18, 2017

Come installation day, ~~engineer~~ tick box muppet commented old connection was wrong, and he had to check I had a 10mm 40amp supply for the new one. He also used a bit of 10mm tw&e from cooker outlet to oven.

corrected that 4U.

Midwest · Dec 18, 2017

telectrix said:
Come installation day, ~~engineer~~ tick box muppet commented old connection was wrong, and he had to check I had a 10mm 40amp supply for the new one. He also used a bit of 10mm tw&e from cooker outlet to oven.

corrected that 4U.

I was being polite. He said he was gas safe whatever (hope he was, 'cos he connected gas) and ..........what for it.............'Part P'dd' until last year, when his company stopped registering them.

telectrix · Dec 18, 2017

should have got a plumber in, then you could run the 15kW shower and the upstairs lights from the same 6mm cooker circuit

Midwest · Dec 18, 2017

Midwest said:
I've been meaning to clamp the thing on start up, just to see how many amps its pulling and for how long.

Well really bored and run out of

[ElectriciansForums.net] Cooker supply 12kw correct cable size

So decided to clamp our 8.6kW cooker. Now meter's bit of a cheapie, and probably needs calibrating. But here's what I got on 244V; 39.4A.

By my calcu's should of been tad over 35A. Run it for a min or so, to allow things to settle.

Spoon · Dec 18, 2017

Why the Dumb & Disagree on @Midwest post?

DPG · Dec 18, 2017

Is it not obvious? He's run out of beer.

Adamk · Dec 18, 2017

Spoon said:
Why the Dumb & Disagree on @Midwest post?

Hasn’t took diversity into account... he’s just done 8600/240 which isn’t correct.... but mainly causes he’s ran out of beer

Spoon said:
Why the Dumb & Disagree on @Midwest post?

davesparks · Dec 18, 2017

Midwest said:
Well really bored and run out of View attachment 39827 So decided to clamp our 8.6kW cooker. Now meter's bit of a cheapie, and probably needs calibrating. But here's what I got on 244V; 39.4A.

By my calcu's should of been tad over 35A. Run it for a min or so, to allow things to settle.

It takes more than a minute for the thermostats to start cutting out and back in which gives the diversity in the cooker.

Diversity takes in to account the fact that when cooking you don’t turn everything on at once, different things take different times to cook so in real use not all elements are switched on at once.

Spoon · Dec 18, 2017

Adamk said:
Hasn’t took diversity into account... he’s just done 8600/240 which isn’t correct.... but mainly causes he’s ran out of beer

But he's just done what he suggested... "'I've been meaning to clamp the thing on start up, just to see how many amps its pulling and for how long"...

Midwest · Dec 18, 2017

Okay so I couldn't be arse'd to stand out in the cold for your aresholes to allow the thermostats to cut in etc. Point I was trying to make was worst case situation, was max amps. Still be happy to connect to 32A 6mm supply. Jesus opps Holy Mary, cripes just be a bit more little horizontal you lot, its Xmas

telectrix · Dec 18, 2017

Midwest said:
Okay so I couldn't be arse'd to stand out in the cold for your aresholes to allow the thermostats to cut in etc. Point I was trying to make was worst case situation, was max amps. Still be happy to connect to 32A 6mm supply. Jesus opps Holy Mary, cripes just be a bit more little horizontal you lot, its Xmas

you might notice that i made no comment on your previous post so far.
39A...........

Toneyz · Dec 18, 2017

DPG said:
Is it not obvious? He's run out of beer.

Now that is dumb.

DPG · Dec 18, 2017

Midwest said:
Okay so I couldn't be arse'd to stand out in the cold for your aresholes to allow the thermostats to cut in etc. Point I was trying to make was worst case situation, was max amps. Still be happy to connect to 32A 6mm supply. Jesus opps Holy Mary, cripes just be a bit more little horizontal you lot, its Xmas

I'm with you Middy. Except the running out of beer bit - do try harder!

telectrix · Dec 18, 2017

anthonybragg said:
Now that is dumb.

what's dumb? DPG's post or running out of beer?

Toneyz · Dec 18, 2017

telectrix said:
what's dumb? DPG's post or running out of beer?

Tel, now that is a silly question.

telectrix · Dec 18, 2017

anthonybragg said:
Tel, now that is a silly question.

but it did provoke a silly answer. QED.

Spud28 · Dec 19, 2017

I just fitted a rangemaster elan induction at home, instructions stipulated 10mm and 40A MCB, I wondered how id fair if I fitted it to a 6mm cable with warranty etc and at over 2 grand I wasn't taking chances. I commented to the missus that 6 of us grew up with four burners, 1 oven and an eye level grill that took your eyebrows every time you lit it with a match (or piece of paper!)

old plodder · Dec 23, 2017

Now then Rangemaster. I had this one with a customer earlier this year.She had paid for delivery and fitment. On arrival fitter said its only 6mm cable needs to be 10mm and 40a breaker. It was returned and she contacted me. Silly thing was it was the new version of the one she was replacing.With divercity it was pushing 29.5 A. The Rangemaster book says 10mm and 40 a but if you dig on their web site it states they are ok on 6mm and 32A mcb. I presented her with a print off from the site. the next day the range and another sparky turned up, he agreed what she had been told was bull. He installed it tested it and went on his way. This pathetic Christmas dinner senario does not happen. This lady cookes a Massive meal every week end for 12+ people and has never tripped. I also did a clamp test on a new install and after 90 seconds with every thing switched on (4 induction rings and a fan oven/grill) the current dropped like a stone to single figures. You could if you wanted fit a 40A breaker to a 6mm cable under certain conditions is not a problem.

Midwest · Dec 23, 2017

old plodder said:
Now then Rangemaster. I had this one with a customer earlier this year.She had paid for delivery and fitment. On arrival fitter said its only 6mm cable needs to be 10mm and 40a breaker. It was returned and she contacted me. Silly thing was it was the new version of the one she was replacing.With divercity it was pushing 29.5 A. The Rangemaster book says 10mm and 40 a but if you dig on their web site it states they are ok on 6mm and 32A mcb. I presented her with a print off from the site. the next day the range and another sparky turned up, he agreed what she had been told was bull. He installed it tested it and went on his way. This pathetic Christmas dinner senario does not happen. This lady cookes a Massive meal every week end for 12+ people and has never tripped. I also did a clamp test on a new install and after 90 seconds with every thing switched on (4 induction rings and a fan oven/grill) the current dropped like a stone to single figures. You could if you wanted fit a 40A breaker to a 6mm cable under certain conditions is not a problem.

His name wasn't Steve was it? He said my Rangemaster had to be connected to a 40A supply & 10mm cable.

Midwest · Dec 23, 2017

old plodder said:
Now then Rangemaster. I had this one with a customer earlier this year.She had paid for delivery and fitment. On arrival fitter said its only 6mm cable needs to be 10mm and 40a breaker. It was returned and she contacted me. Silly thing was it was the new version of the one she was replacing.With divercity it was pushing 29.5 A. The Rangemaster book says 10mm and 40 a but if you dig on their web site it states they are ok on 6mm and 32A mcb. I presented her with a print off from the site. the next day the range and another sparky turned up, he agreed what she had been told was bull. He installed it tested it and went on his way. This pathetic Christmas dinner senario does not happen. This lady cookes a Massive meal every week end for 12+ people and has never tripped. I also did a clamp test on a new install and after 90 seconds with every thing switched on (4 induction rings and a fan oven/grill) the current dropped like a stone to single figures. You could if you wanted fit a 40A breaker to a 6mm cable under certain conditions is not a problem.

His name wasn't Steve was it? He said my Rangemaster had to be connected to a 40A supply & 10mm cable.

old plodder · Dec 23, 2017

Per Rangemaster FAQ dated 10/11/16 "Ceramic and induction models may be connected to a suitable 6mm cable with a 32A breaker (providing the isolator switch does not incorporate a 13A socket)"
It also states in the owners handbook " Installation to comply with BS7671", which tells you how to calculate and apply diversity. My customers argument to Rangemaster was (which I advised her to ask) "are you saying this product will not comply or meet with the conditions of BS7671?
It had the required result. Manufactures also have an obligation to the customer for their product to meet a specified standard.

Midwest · Dec 23, 2017

To be fair, my Rangemaster electrical instructions, just state it must be installed by a qualified electrician in compliance with BS7671, maximum size cables that can be terminated, and max load of appliance. Sort of 'down to you in the studio'.

old plodder · Dec 23, 2017

Yup a qualified sparky will work it out and design a new circuit or in this case confirm the existing circuit is suitable as per BS 7671. Rangemaster does say on the FAQ page 10mm cable and a 45A breaker will give "greater flexibility", but, if all you need is to replace your range with another one and don't want the flexibility one can only assume there was an ulterior motive by the electrician. I wonder what it was!!!

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