Induction Hob - what is the maximum rated power hob I can install in conjunction with a with a 3.5KW oven on a 32A cooker circuit?

[flameport]

almost nobody has to comply with what BS7671 or the IET say.

While that is true, anyone who choses to not comply with BS7671 will need a substantial and robust alternative, such as a standard from some other country or an equivalent used within a certain industry, plus reasons why using an alternative is considered necessary in those particular circumstances.

Just saying ' doesn't comply with BS7671' is not an option.

 

[davelx]

While that is true, anyone who choses to not comply with BS7671 will need a substantial and robust alternative, such as a standard from some other country or an equivalent used within a certain industry, plus reasons why using an alternative is considered necessary in those particular circumstances.

Just saying ' doesn't comply with BS7671' is not an option.

Yes, I agree
That's not the point.

 

[EFLImpudence]

That's a condition of their registration with a trade body. At their choice.

Well - yes but not really a trade body as such but a mandatory membership if certain work is done.

To do that work might be described as a personal choice but I don't think it is what is really meant by the term.


Like having a driving licence is a personal choice but if you are a taxi driver...

 

[P drop]

I suppose it is regrettable that we, the customers, must treat safety-critical trades (eg electrical and gas) with the same scepticism as other potential "rogue tradesmen" who over-charge for strictly unnecessary, over-inflated jobs. I have not heard from the Checkatrade electrician who said he would quote me for a new 10mm circuit just for the hob, plus an additional consumer unit; and I dont expect to because he realised I was an informed customer. He even asked "where did you get your knowledge from?" If I had been the archetypal "little old lady" customer I suggest he would have quoted.

Here is another angle. In the absence of an IEC/MEIWC for specific electrical work, an acceptable solution when renting/selling a property could be to have a Part P-certified inspector carry out an Electrical Installation Condition Report (EICR). I would expect an inspector MUST apply diversity, where permitted, if necessary to assess a circuit (eg cooker) as compliant.

​

 

[EFLImpudence]

Here is another angle. In the absence of an IEC/MEIWC for specific electrical work, an acceptable solution when renting/selling a property could be to have a Part P-certified inspector carry out an Electrical Installation Condition Report (EICR).

For a property sale it would be up to the buyer to have any inspections done if he wanted.

There is no point the seller doing anything as it probably would not be trusted.

It's no different than selling a car. Do you want the house or not?


For rented properties, there are new requirements which are very badly thought out,

I would expect an inspector MUST apply diversity, where permitted, if necessary to assess a circuit (eg cooker) as compliant.

Yes, of course; it is standard practice.

Virtually all cooker circuits are 32A with 6mm² T&E (6mm² for the reason I stated above in post #24) and are good for virtually all cooking appliances fitted in domestic premises.

 

[ebee]

just saying ' doesn't comply with BS7671' is not an option.

True enough, all though BS7671 is not in itself a statutory document it nearly always be treated as if it actually is almost all of the time.
You will "probably" comply with all relevant conditions that apply to you in law.
If you have the ability to use an alternative (your own or that of a "civilised country") then you might use that instead. In any event we have to include the risk that we might have to appear in front of a bloke in a wig and attempt to justify our actions as being reasonable whilst we are gripping the rail and trying to convince them that we are in compliance with the laws of the land.

It`s not law but pretend it is. The same thoughts might also apply to the Highway Code in relation to road traffic acts too. One of you might know more about that thought?

 

[yo61]

I'm just running into a similar problem with a new build property, except my options to resolve it are limited.

Situation:

I'm buying a new-build property, I get to design the kitchen and specify the appliances. I've chosen a 90cm Neff induction hob with a total power requirement of 11.1kW. I chose it for the feature set, and to go with all the other appliances, esp. to be able to control the ceiling-mounted extractor hood.

The kitchen has had 6mm copper installed. The electrician used by the developer is saying he will not certify the installation if this hob is installed, "for safety reasons".

The hob has a "Power Limitation" feature which allows total power used by the hob to be limited.

My view is that the “Power Limitation” setting is not a safety feature, it is to prevent the appliance from pulling too much current and tripping the breaker, ie. it is to prevent inconvenience. The only bad thing that will happen if the power limitation feature is inadvertently disabled is that the breaker on the circuit will trip to protect the wiring, which is exactly what it’s designed to do. Also, bear in mind that this will only happen if the hob is operating at 86% of max capacity, ie. all 5 zones are operating at 86% of their maximum setting, which simply isn’t going to happen in any kind of normal use.

From what I've read in this thread, this hob should be fine on 6mm copper - is that correct?

Not sure how I'm going to resolve this.

 

[pete01]

You are right the electrician is wrong....a 6mm 32 amp cooker circuit can have upto 15kw of appliances connected to it....

Some mad men even say 20kw

 

[EFLImpudence]

From what I've read in this thread, this hob should be fine on 6mm copper - is that correct?

Yes - and with an oven as well.

You seem more knowledgeable than the "electrician".

Find one who knows what he is doing.

 

[EFLImpudence]

Some mad men even say 20kw

Without integral socket in the cooker switch.

Do the maths.

 

[pete01]

Without integral socket in the cooker switch.

Do the maths.

OK

 

[EFLImpudence]

Typo - 30%

 

[pete01]

Typo - 30%

No I took off 70%?

 

[EFLImpudence]

Oh ok.

 

[yo61]

Thanks for all replies.

You are right the electrician is wrong....a 6mm 32 amp cooker circuit can have upto 15kw of appliances connected to it....

Some mad men even say 20kw

What can I quote to the developer (and ultimately, the electrician) to persuade him that this is fine?

Incidentally, the hob specification says:

• Connected load: 11.1 KW
• 4.6kW power output (20A); current management options for 16A,13A or 10A connection: limit the maximum power if needed(depends on fuse protection of electric installation).

This seems to suggest a 20A supply is sufficient? Or am I reading that wrong?

R.