Fitting An A New Electric Cooker

[Max6979]

A friend has asked me to help him fit his new 9.4kW electric cooker. I have done some calculations and  know that the desing current is 40.87A . He has a 30A rewireable fuse - I have advised him that he will need to change to a 45A fuse.

The instruction manual advises either 1.5mm or 4mm cable. I have advised him that I will need to do  a cable size calculation as 1.5mm is too small . The distance from the CU to the cooker is less than 5 metres.

I have also advised him that he may need to change his CU . My friend has told me that the previous cooker worked Ok on the 30A fuse and told me that the wiring seemed bigger than 6mm - may be 8mm.

Is there a way to fit the cooker without needing to change the CU as I want to keep costs down- am I missing anything?

 

[SPECIAL LOCATION]

Probably diversity and competence at a guess??

:C

 

[ProDave]

Like for like swap (old cooker for new on existing, unaltered circuit) then you don't need to upgrade anything.

But I question your competence to do this.

 

[Max6979]

I did a diversity calculation ie 10A and 30% of remainder( from On Site Guide) and the figure came to 31.61A . I have asked how many times will the cooker be used with all the rings on and he has stated that the cooker will often be used for religious gatherings , feasts etc so full load will be expected often and frequnetly.

In regard to competence I am never too proud to ask a question nor would I attempt anything without asking questions and I am in process of gaining a level 3 C & G 2365 at evening classess at a local college ( I already have the level 2 so I am not a 5ww- no offence to any 5ww who may read this forum ).

 

[Max6979]

Just confused-  thought if the design voltage was 40.87A then the overcurrent protective device should be say 45A irrespective of the diversity calculation. If anyone can explain I would be grateful.

 

[BES]

Max. Check your calcs a 9.4kw oven with no socket outlet is about 19.4 amps.

 

[Andy™]

I did a diversity calculation ie 10A and 30% of remainder( from On Site Guide) and the figure came to 31.61A

erm... maybe start with the basics.

40.87a -10 = 30.87a. 30% of this is 9.3a. + the 10a. = 19.3a. not 31.61

maybe you really are a 5ww...

and why change the CU just to replace a cooker? oh yes, you dont have a clue what the regs actually state, and you think every small job is a new CU. wonder how much that would be? £600 + VAT. after all, it would probably take you 2 days byt eh time you keep going to a forum to ask questions

 

[Max6979]

Only asking - sulk :coat

 

[Andy™]

problem being, whilst you probably are trying your best, you are not yet competent. asking basic questions and lack of ability to work out diversity proves that. one day you may be competent, but until then stick to what you can do

 

[Max6979]

I'll get my coat. :coat

 

[Andy™]

and there is no such size as 8mm

 

[Max6979]

Thanks for all the infornmative , helpful and useful comments. My question has been answered . I thank you.