11,5kW range cooker

[Stever_777]

Hi guys, I'm pricing a job, it's an extension for a new kitchen and dining area. There' s a 11,5kW range cooker going in, dishwasher, cooker hood, fridge freezer, 5 DSO's, and 2 lighting points with intermediate switching. Central heating is combi. The run to cooker is about 24m. Would I be right in saying that I'll need a 10mm T & E and 50A MCB for the cooker?The DNO's BS 1361 fuse is 60A and it looks like the tails are 16mm. Anything from you more experienced guys what I should take into consideration while pricing?Thanks

 

[Sickmick]

What other circuits are already in the board?

 

[robsparky1975]

cooker with diversity would be first 10 amps then 30% of remainder of the load,after calculating this load and all others the maximum demand of the installation needs to be calculated and if you believe its too much for existing supply then the dno might need a call.

 

[Stever_777]

The board is a mess sickmick, I'm gonna have to rewire but my guess is that alot of those cables will be ripped out, old electric shower, pld central heating & cooker circuit etc, it's not that big a place so looks like just lights and ring main mate.

 

[telectrix]

6mm is adequate for the cooker on a 32AMCB if insulation problems, 40A if clipped direct . VD 4.3V assuming 23A with diversity applied.

 

[Stever_777]

cooker with diversity would be first 10 amps then 30% of remainder of the load,after calculating this load and all others the maximum demand of the installation needs to be calculated and if you believe its too much for existing supply then the dno might need a call.

Thanks mate

 

[Engineer54]

Stever,

I've said it before, and i'll say it again, .....A 30/32A MCB sitting on 6mm cable is good for cooking appliances upto 15KW. SO NO, you don't need a 50A MCB, and you don't need 10mm cable either, ...not for a tiny cooker load of 11.5KW....

 

[NMc]

BS7671 require you to ensure that the existing DNO supply and earthing arrangements are adequate

On-site guide explains have to calculate the additional load

As a competent person you are going to need to do a bit of a calculation. We don't know the job and posts here are only going to give opinions. If you are designing the installation you will be responsible

 

[Stever_777]

Stever,I've said it before, and i'll say it again, .....A 30/32A MCB sitting on 6mm cable is good for cooking appliances upto 15KW. SO NO, you don't need a 50A MCB, and you don't need 10mm cable either, ...not for a tiny cooker load of 11.5KW....

Ok, dont bite my head off thanks for advice.

 

[Stever_777]

6mm is adequate for the cooker on a 32AMCB if insulation problems, 40A if clipped direct . VD 4.3V assuming 23A with diversity applied.

Thanks Telectrix

 

[telectrix]

Stever,

I've said it before, and i'll say it again, .....A 30/32A MCB sitting on 6mm cable is good for cooking appliances upto 15KW. SO NO, you don't need a 50A MCB, and you don't need 10mm cable either, ...not for a tiny cooker load of 11.5KW....

couldn't agree more.

 

[Stever_777]

BS7671 require you to ensure that the existing DNO supply and earthing arrangements are adequateOn-site guide explains have to calculate the additional loadAs a competent person you are going to need to do a bit of a calculation. We don't know the job and posts here are only going to give opinions. If you are designing the installation you will be responsible

Too true, I understand. I'm just new to working all this out, my history is flat bashing in London, so I'd just turn up and smash them out for a company, but now I am the company.Thanks

 

[lennox]

sorry if i am way off but woundnt the tails need upgrading?i thought they always had to be 25mm?

 

[electromonkey]

Stever,

I've said it before, and i'll say it again, .....A 30/32A MCB sitting on 6mm cable is good for cooking appliances upto 15KW. SO NO, you don't need a 50A MCB, and you don't need 10mm cable either, ...not for a tiny cooker load of 11.5KW....

HAHA Your no nonsense approach to posts does at times give me a chuckle when I read them Engineer54.

My last call for today was for a customer who's electric shower was playing up. I got there to find (amongst other things) an 8.5KW shower installed on a 32A MCB and run from the board to a 60A JB in 2.5 T & E. From the JB to the 40A switch and on to the shower was 6mm T & E. I was expecting to find signs of over heating of the cable at least at the termination points and to my surprise, there were none. I then carried out an IR test. Everything was dandy. I then did a cable calc for the circuit and guess what? Yep, 2.5 was what I came up with. I think this was done more in luck than in judgement by the former home owner and obviously keen DIYer though.

I'm back there next week for a CU upgrade and he wants a 10KW shower so I think I'll upgrade the 2.5!

 

[SPARTYKUS]

HAHA Your no nonsense approach to posts does at times give me a chuckle when I read them Engineer54.

My last call for today was for a customer who's electric shower was playing up. I got there to find (amongst other things) an 8.5KW shower installed on a 32A MCB and run from the board to a 60A JB in 2.5 T & E. From the JB to the 40A switch and on to the shower was 6mm T & E. I was expecting to find signs of over heating of the cable at least at the termination points and to my surprise, there were none. I then carried out an IR test. Everything was dandy. I then did a cable calc for the circuit and guess what? Yep, 2.5 was what I came up with. I think this was done more in luck than in judgement by the former home owner and obviously keen DIYer though.

I'm back there next week for a CU upgrade and he wants a 10KW shower so I think I'll upgrade the 2.5!

What calc is that electromonkey?