Yet another induction hob question

[Genesis1923]

Hello

I have a new AEG induction hob rated at 7.4kw max using power sharing but AEG do not specify a cable size or mcb rating nor will they answer the question I submitted to them by email. I think their position is that it is down to the electrician to decide.

The configuration is as follows:

Cooking zone 1 - 2300/3700/10
Cooking zone 2 - 1800/2800/10
Cooking zone 3 - 1400/2500/4
Cooking zone 4 - 1800/2800/10

Where the values represent Nominal power (max)/Power function/Power max duration (mins)

As the work is notifiable I have asked a local qualified electrician to quote for a new radial circuit and he has suggested that I need 10mm cable on a 40 amp mcb because he does not apply diversity and therefore the amperage will be 32.174 at 230 volts, hence the need to go to a 40 amp mcb and 10mm cable. He is prepared to install 6mm cable on a 32 amp mcb but will not be responsible for the frequent tripping out that he feels I may experience.

Having read a number of different forums I get the impression that most electricians (but not all) would apply diversity and I would appreciate the views of those of you experienced in this area as to whether I am likely to regret not going with the 10mm cable and 40 amp mcb. My personal feeling is that it won't be a problem as I am unlikely to ever be using all four zones on the 'power' function at the same time. Using all four zones on maximum (but without 'power') would require 7.3kw, so just within the limits of a 32 amp mcb but this isn't going to happen either.

The only reason for posting the question is that ideally I would like to use the existing cooker switch for the induction hob (it's right next to it) and run a new radial to the double oven which is currently on the existing cooker circuit. The existing circuit is 6mm cable on a 32 amp mcb.

The existing cable is 9.5 metres from the CU to the cooker switch and passes through the ceiling void and is then enclosed in conduit behind a tiled wall. It does not pass through any insulation.

I would very much appreciate your thoughts based on personal experience.

Thanks in advance.

 

[dave274]

Just get a different electrician who will apply diversity.

 

[telectrix]

Just get a different electrician who knows what he's doing..

corrected that for you.

6mm on a 32A MCB is fine. ref. method permitting you could use 6mm on a 40A. (Iz =47A ref. method C ).

 

[Pauls0212]

If the electrician uses 240v, which is more likely, then a 32 mcb will be ok as max would be less than 31 amps. Ask the "electrician" to check whether it is 230 or 240v.

 

[mattg4321]

The electrician is wrong in my opinion.

Diversity on cooking appliances in domestic locations is first 10A and 30% of remainder. Has been for years and years. Following that rule has never let me down. The existing circuit will easily cope with the load.

I fairly often install single ovens and hobs such as yours on a single 32A supply. Hob is usually around 7kW and oven around 2.7kW

 

[Genesis1923]

Many thanks to all for taking the time to reply. There are other local electricians and I will get another quote which will hopefully be in line with the opinions expressed here.

Thanks again.