My head hurts - cooker cable calc

[Octopus]

Ok, had far too much to drink last night and wish I'd done this estimate yesterday but didn't and need a sanity check.

New dual fuel cooker being installed (gas ovens) and electric hob

This is the electrical spec

Power ratings - hob 1 x 1kW, 2 x 1.7 kW, 1 x 3.0 kW, 1 x 3.5 kW, 2 x 1.1kW

Total hob rating @ 230v 13.25 kW

Maximum electrical load @ 230v 11.8 kW = 51A

So we all know it won't draw 51 amps and looking at the run I'd prefer to install a 6mm cable which would be good for approx 38A


Help!

 

[i=p/u]

10A plus 30% = abou y 22.1A

 

[Octopus]

2nd time round I came up with 28A but then my doubts crept in and you've come up with 22A

Where's the aspirin!

 

[telectrix]

6mm on a 32A MCB..... sorrted.

 

[Octopus]

6mm on a 32A MCB..... sorrted.

Thats what I originally thought but wanted to make sure!

 

[telectrix]

13,250/230 = 57.6A

10A + ( 0.3 x 47.6) = 24.28A.

 

[Octopus]

13,250/230 = 57.6A

10A + ( 0.3 x 47.6) = 24.28A.

Thanks. Interestingly if you add up the individual loads as listed its slightly less.

Ta chaps. Estimate will be sent after the next strong coffee !

 

[i=p/u]

and as you asked engineer and accepted answer 11.99 this way

 

[Engineer54]

Thanks. Interestingly if you add up the individual loads as listed its slightly less.

Ta chaps. Estimate will be sent after the next strong coffee !

Possibly the total KW rating includes the oven fan and oven light and controls...

 

[i=p/u]

Never assume as are AN electrician and you dont know characteristics or distance of cooker run

6mm on a 32a mcb..... Sorrted.

- - - Updated - - -

WHAT GOOD IS POSSIBLY ????

Possibly the total KW rating includes the oven fan and oven light and controls...

 

[Engineer54]

Never assume as are AN electrician and you dont know characteristics or distance of cooker run




- - WHAT GOOD IS POSSIBLY ????

So you tell me what difference will it make then, the quoted KW remains the Same??


6mm on a 32A MCB is good for cooker loads up to 15KW. You would have to go some, for distance and cable factors, to change this typical circuit compliance!! Literary Millions of homes in the UK will have exactly the same circuit make-up.

 

[i=p/u]

anything more than 50m and installation methods could stop it from complying , now we didnt have enough info to:81: just say 32A 6mm spot on

 

[i=p/u]

and foget about half the country, and concentrate on this ...

 

[MDJ]

I came up with 23.22 amps, however I have have a few sunday beers haha, a 6mm2 will be fine IMO.

 

[Octopus]

The run is about 10 meters. My head did hurt at the time. The aspirin and coffee have worked.

 

[Engineer54]

anything more than 50m and installation methods could stop it from complying , now we didnt have enough info to:81: just say 32A 6mm spot on

Now we are being foolish aren't we, 50m on a cooker circuit, your now in the realms of a mansion!!

and foget about half the country, and concentrate on this ...

Yeah forget about 60+ years of tried and proven way doing things, concentrate on my daft statement!!


Errr, Murdoch is an electrician not a DIY'er!! lol!!

 

[i=p/u]

aye assume nothing is all im saying... i do know 6mm is the obvious but why not save money and put on 4mm .....

 

[MDJ]

aye assume nothing is all im saying... i do know 6mm is the obvious but why not save money and put on 4mm .....

were back to whats good practice again, as mentioned countless of times the regs are the minimum standards, it depends I suppose on the individual sparks good practice standards, I can't imagine any electrician installing a 4mm2 cable on a 11 or 12kw cooker regardless of whether it is over the top or not, there has to be a point where we say rollocks to regs, I am doing a better Job than these minimum requirements.

 

[i=p/u]

but you could possibly still use 32A breaker... aye its just me bored tempting myself to argue who knows more with e54:24:

 

[Geoffsd]

Manufacturers figure still quoted at 240V I expect.

Saves a little.

 

[yellowvanman]

Isn't the use of 6mm on a 32A for a cooker inherited from the days of BS3036 fuses?

 

[Geoffsd]

Isn't the use of 6mm on a 32A for a cooker inherited from the days of BS3036 fuses?

I don't understand.

3036s are 30A.

6mm and 32A is good for at least 15kW cookers.
Even more without the 5A for socket at the switch.

 

[yellowvanman]

I don't understand.

3036s are 30A.

6mm and 32A is good for at least 15kW cookers.
Even more without the 5A for socket at the switch.

Sorry, you're correct about the 30A

But 433.1.3 dictates cable size for a BS3036

6mm clipped direct has a CCC of 47A
47 x 0.725 = 34A

Whilst 4mm has a CCC of 37A - OK for 32A BS60898
37 x 0.725 = 26.8A - not enough for 30A BS3036 fuse

 

[MDJ]

BEST TO PULL OUT THE 3036, go down to the river and throw it as hard as you can and see if you can reach the other side on the bank opposite haha, then take a circuit breaker from the van via the wholesalers and push it into the gap left from the 3036, a much better solution IMO.

 

[yellowvanman]

best to pull out the 3036, go down to the river and throw it as hard as you can and see if you can reach the other side on the bank opposite haha, then take a circuit breaker from the van via the wholesalers and push it into the gap left from the 3036, a much better solution imo.

can't disagree with that!

 

[i=p/u]

i can cause my mothers house whichhas had same installation for 30 odd years and never any problems till i started messing aroundlol

 

[MDJ]

you could put a 6" nail across a live and neutral in some installations and the 3036 wouldn't blow lmao, I know theres a few devoted 3036 supporters here but the day they stopped making them for modern DBs and replaced them with 3971 and 60898s was the best thing that happened IMO haha, silver foil and a bit of 2.5 stripped earth wire was a common fuse wire, yup love 3036s haha

 

[i=p/u]

dangerous in that sense yes, good riddings might get cu and fit when at mothers for 2 weeks at christmas

 

[Geoffsd]

Sorry, you're correct about the 30A

But 433.1.3 dictates cable size for a BS3036

6mm clipped direct has a CCC of 47A
47 x 0.725 = 34A

Whilst 4mm has a CCC of 37A - OK for 32A BS60898
37 x 0.725 = 26.8A - not enough for 30A BS3036 fuse

Ah. I see what you mean.

Good point. I hadn't thought of it like that.