New hob - how many amps

[richardadc]

I'm looking to replace my old electric hob with an Induction one (Indesit VIA640C). I've currently got a 32amp fuse in my fuse box which is used for the hob and a single oven (which runs off a 13amp plug). The new hob uses a max of 7,200W. Will this be OK as a straight replacement or will wiring and fuses need to be changed?

 

[xr4x4]

7200watts divide by 230v = 31.30 amps.

 

[richardadc]

So does that mean with the oven running at the same time (which i believe is about 2500 Watts) i need to update the fuse in the consumer unit or do i work it out on the basis that it's unlikely that all will be on at once?

Many thanks!

 

[Taylortwocities]

The hob will need that cooker circuit all to itself. You'll need to find somewhere else to connect the oven.
If the oven is really only 2500 watts you can just plug it in to a reguilar socket with a 13A plug.

 

[richardadc]

The hob will need that cooker circuit all to itself. You'll need to find somewhere else to connect the oven.
If the oven is really only 2500 watts you can just plug it in to a reguilar socket with a 13A plug.

I don't have another 13A socket easily available so it would mean updating that circuit. Is there anyway around it? I believe my current hob is 6K Watts - will another 1.2K Watts make that much difference?

 

[ericmark]

Most induction hobs include a "Boost" function with means if you only use two rings rather than 4 the two run at a higher wattage including when they switch on and off to control temperature.

As a results all the old calculations for diversity no longer count.

However reading the Instructions it seems your model does not have the boost function.

So although 2 x 1.4Kw + 2 x 2.2Kw + 2.5Kw = 42A it is likely that the average consumption will be below 32A and as a result you may well find most of the time it will run fine on 32A supply. Christmas you may find it will trip and the worry is of course with loss of supply you also loss all fans and the unit could overheat. But I would think this would be unlikely.

So I would expect in your case diversity will allow you to use all on 32A MCB but there can't be a guarantee on that of course. If you are on a fuse I would ensure you have a spare as if it should blow and you don't replace without fans to cool the unit it could overheat and be damaged.

 

[bernardgreen]

7200watts divide by 230v = 31.30 amps.

7200 watts at 230 volts is the rating.

If the local supply voltage is higher than 230 then it is likely the wattage will be higher and the current will increase.

That is the case with resistance heating elements. Possibly induction hobs are regulated but even so running so close to the fuse rating is not good practise.

Do NOT change the fuse as the cable may not be able to safely carry more that the 32 amp.

 

[Taylortwocities]

Sorry, I think I must have missed something

P = V x I

SO

I = P/V

So if the voltage is higher then the current decreases

At 220v the 7200W unit draws 32.7 amps
At 250v the same unit draws 28.8 amps

 

[holmslaw]

..

 

[ericmark]

Sorry, I think I must have missed something

P = V x I

SO

I = P/V

So if the voltage is higher then the current decreases

At 220v the 7200W unit draws 32.7 amps
At 250v the same unit draws 28.8 amps

Yes have missed something Power/Ratted Voltage = 7200/230 = 31.30A = 7.35 ohms the ohms are fixed so 250V/7.35 ohms = 34A or 8507 Watts.
Your getting ratted voltage and actual voltage mixed up.

However with an induction hob as "bernardgreen" says this may be corrected by the electronics in the same way as your LAPTOP with switch mode power supplies so you may be correct but since I have never reverse engineered an induction hob I don't know.

However as long as the fuse or MCB is not changed there is no danger to personnel in connecting both hob and oven however since the hob relies on fans for cooling there may be a danger to the hob in that it could cook itself.

Personally I think it is low risk but they are not cheap and "richardadc" has to decide if he wants to take a chance with his new hob. I am sure if I add up the rings, grill and oven on my stand alone unit it will exceed 32A and it's been fitted now since 1981 and never tripped the MCB and I am sure if I found out the Guide to 16th Edition and followed the diversity recommendation it would permit well over the base 32A.

 

[richardadc]

Thank you all for your help. I've worked out i can connect the oven to a socket currently used by the washing machine (as long as i convert it to a double socket). As I'm going to need a lead from the oven to the socket that's about about 2 meters longer than the other one can you please tell me what type i should buy? Will I also need to get one for the hob or will that come with one?

 

[Taylortwocities]

Have alook at the instructions (link above). It says there that the hob comes with a cable and tells you how to connect it.

For the oven I would recommend a length of 2.5mm² three core flex and use a suitable junction box to connect it to the existing cable.