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Induction Hob again

Former Community Member
Former Community Member
I hope that you don’t find me impudent but I am having difficulty finding an electrician to explain why they will not install the induction hob and double oven that we are looking to fit in our new kitchen.
We have chosen a hob 7.4 kW and oven 6.3 kW. The cooker radial circuit has 6mm2 cable with 40A MCB. The run is some 12 m. The house was built (converted) in 2002 and inspected last year (DPN18C). We cannot run an extra cable because the CU is separated from the kitchen without a horizontal floor or roof space and presumably runs the existing cable through the stud walls.
The kitchen fitting company electrician has visited but won’t carry out the work unless we sign an indemnity as it would invalidate our insurance and the appliance guarantee. He suggested instead two plug-in ovens which we could add to the ring main. I have contacted four other local electricians but they all use 13.7 kW means 59.7 A which means 10 mm cable and ignore my request to consider diversity.
Should I give up and accept the two oven solution or perhaps a gas oven?
Do you know of a way of finding someone who understands diversity?
Am I simply wrong?

Parents
  • I am with the electricians on this. Putting both appliances on one cable that is protected by a 40A MCB could cause the circuit breaker to trip under full load conditions. Quite rightly they want to protect themselves against any claim and want to pass that liability to you. You appear not to want to accept that risk but expect them to do so.


    The over riding Regulation in BS 7671 requires the designer and installer to take notice of the manufacturers instructions. What does the manufacturer say about the cable and the supply circuit breaker for each appliance?


    How is the cable run, in conduit or trunking?


    Diversity should not be applied to circuits supplying individual appliances to select the supply cable. The cable should be sized in accordance with the manufacturers instructions or the plated rating. Diversity factors should be used for distribution circuits or the whole installation. Yes I know that the OSG says something that reads differently but I would not mind betting that will change in the next edition.
Reply
  • I am with the electricians on this. Putting both appliances on one cable that is protected by a 40A MCB could cause the circuit breaker to trip under full load conditions. Quite rightly they want to protect themselves against any claim and want to pass that liability to you. You appear not to want to accept that risk but expect them to do so.


    The over riding Regulation in BS 7671 requires the designer and installer to take notice of the manufacturers instructions. What does the manufacturer say about the cable and the supply circuit breaker for each appliance?


    How is the cable run, in conduit or trunking?


    Diversity should not be applied to circuits supplying individual appliances to select the supply cable. The cable should be sized in accordance with the manufacturers instructions or the plated rating. Diversity factors should be used for distribution circuits or the whole installation. Yes I know that the OSG says something that reads differently but I would not mind betting that will change in the next edition.
Children
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