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Cable Diversity for Induction Hob

Former Community Member
Former Community Member
Hi all,


I have been tasked with wiring an induction hob, and I’m fairly new to install work on my own having just qualified myself and venturing out on my own. 


The Hob is rated at 7.35kW.

In my head, and applying the cable diversity factors-

7350w divided by 230v =31.95amps.

Take off the first 10amps =21.95amps

21.95x30% = 6.58amps

6.58amps+10amps =16.58amps Total.


Plus 5amps if there is a 13amp socket involved, which there isn’t in this case.


so with that in mind, I’d be fine wiring the circuit with reference method C (clipped direct) in 2.5mm T+E right??! Although saying that, my thoughts are to wire using 6mm T+E just in case future appliances vary! 

does this seem logical or should I just keep it as a 2.5mm circuit on a 20amp MCB.


any advice would be greatly appreciated. Let me know your thoughts?
Parents
  • Hi John.

    That is true if there is a single heating space, but if there are 4 the situation is a bit different. Essentially to use all 4 at full power draw would need 4 big pans on full at once, which is pretty unlikely. A small pan does not get as much power as one that is larger than the marked space. To get full power the thing being heated must be fully coupled to the hob coil, be thick enough to fully load the induction generator, and generally not be too hot. All of these things lead to less loss in the pan base and consequently reduce the power dissipation and supply current. However, there is not much reason to reduce the cable size upon installation, unless it is an existing one being reused. After all 4mm is not hugely more expensive than 2.5 is it, and then you can fit a 32A MCB/RCBO which will cope just fine when you put a commercial pot on the stove 3 feet in diameter filled with 20 gallons of soup, or equivalent metric measurements. I quite like induction hobs if powerful enough, but I haven't found a shaped one yet which fits an INDUCTION WOK with the same heat as the gas, or the WOK either for that matter. A new market, but 10kW please just like the gas!
Reply
  • Hi John.

    That is true if there is a single heating space, but if there are 4 the situation is a bit different. Essentially to use all 4 at full power draw would need 4 big pans on full at once, which is pretty unlikely. A small pan does not get as much power as one that is larger than the marked space. To get full power the thing being heated must be fully coupled to the hob coil, be thick enough to fully load the induction generator, and generally not be too hot. All of these things lead to less loss in the pan base and consequently reduce the power dissipation and supply current. However, there is not much reason to reduce the cable size upon installation, unless it is an existing one being reused. After all 4mm is not hugely more expensive than 2.5 is it, and then you can fit a 32A MCB/RCBO which will cope just fine when you put a commercial pot on the stove 3 feet in diameter filled with 20 gallons of soup, or equivalent metric measurements. I quite like induction hobs if powerful enough, but I haven't found a shaped one yet which fits an INDUCTION WOK with the same heat as the gas, or the WOK either for that matter. A new market, but 10kW please just like the gas!
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