Induction Cooker Electrical Installation

[smithy50]

Hi,

I'm planning on replacing my existing cooker with an Induction one and am looking for some advice regarding the associated electrical installation.

My existing cooker is connected through a 6 sq mm T&E cable and protected by a 32A mcb.

The proposed new cooker is a Rangemaster Excel 110 Induction model with a maximum load of 16.8kW at 230V. The manufacturer recommends connecting it through a 10 sq. mm cable and 45A mcb.

I intend having a new 10 sq. mm cable installed from the consumer unit to the Cooker Control Unit. The new cable will be approximately 15 metres long and it will be clipped under the floorboards.

The existing Consumer Unit is a Hager, but I cannot find a 45A Hager Type B mcb. I can only find 40 and 50A versions. I've had a look at an MK 45A Type B mcb, but the live input connection is not in the same location as the Hager mcb.

I understand that the 10sq. mm cable (in reference method C) should be able to carry about 64A, so from a cable protection point of view I should be able to use a 50A mcb. However, the Cooker Control Unit is rated at 45A, so is this likely to be an issue.

Any advise, or help, would be much appreciated.

Thanks

 

[EFLImpudence]

If your 6mm² cable is clipped to surface or buried in masonry you can put a 45A or 40A MCB on that.
6mm² has a maximum current carrying capacity of 47A.

If you do not have an integral socket on the cooker control switch you can leave it as it is.



However, the delivery installers will not connect it if it is not as they have written down.

 

[JohnW2]

If your 6mm² cable is clipped to surface or buried in masonry you can put a 45A or 40A MCB on that. 6mm² has a maximum current carrying capacity of 47A. If you do not have an integral socket on the cooker control switch you can leave it as it is. However, the delivery installers will not connect it if it is not as they have written down.

I agree with all of that. As you say, it depends upon how much of a silly Jobsworth the installer is. As you say, if there is no socket on the CCU, the existing 6mm² cable and 32A MCB would be OK (indeed, even 4mm² cable may well have been OK). If there is a socket, then (with the installation method described) the 6mm² cable would still be OK, but the MCB would theoretically have to be upgraded to at least 40A.

As you imply, if the cable were upgraded to 10mm², that would only be to satisfy the manufacturer's (electrically unnecessary) 'recommendation'.

smithy50: who is going tro be installing this cooker?

Kind Regards, John

 

[ericmark]

Mine is about same size. Belling says use 32A MCB which I have done been running for 4 years without a problem. The heat areas have a boost function which seems great until you come to use it. With plain water yes it works great betting a kettle to boil water, but with food you can't stir it that fast so it just burns.

What we have is a more economical cooker than any before it. So clearly it must use less not more power.

 

[smithy50]

Firstly, Thanks EFLIpudence, JohnW2 and ericmark for your prompt responses to my post.

I was intending to connect the cooker myself.

The CCU is the large square MK type with an integrated outlet socket. However, the outlet socket never gets used because of its proximity to the cooker. I could fit one of those outlet socket inserts that prevent it from being used inadvertently.

 

[bernardgreen]

but with food you can't stir it that fast so it just burns

Don't you just love crispy porridge.....

 

[ericmark]

I would not bother using any blanks in the socket, main reason they can damage the socket, any item plugged into a socket outlet should be marked BS 1363 if not so marked do not use. See this report on socket blanks when I PAT test they are all removed and the sockets found in noted as possibly requiring replacement.

As to cooker worse case is the MCB trips and since no cooling fans cooker over heats. The latter is really unlikely as with any power cut it could also over heat.

 

[ericmark]

but with food you can't stir it that fast so it just burns

Don't you just love crispy porridge.....

Yes when we first got it we were so eager to show how good it was. It really makes gas look so slow. However we soon realised why there are no options between 9 and full boost as only time you can use full boost is with simple water. We were also thankful by look that we had control knobs, it was only when we came to use mothers with touch controls that we realised how stupid touch controls were. They look good, but are too slow to use the knob is a much faster HMI (human machine interface). So with knobs there is no need to lift a pan to stop it heating.

The fact that when you do lift a pan it auto switches off until pan is returned means less power wasted, what we have found is that it is easy to forget to switch off, there is no red glow to warn you. However after set time it switches off anyway, we have got use to safety features this is a problem when we use a non induction hob. I use the auto boil then simmer a lot and am not really worried about walking into next room to get something when cooker is in use. Really miss it when we go into the caravan and remember what cooking was like.

 

[bernardgreen]

The only good thing about touch controls is they are waterproof and do not suffer from spilt liquid getting under the knob and onto the control PCB.

 

[JohnW2]

I was intending to connect the cooker myself.

Right - in that case you don't have to worry about a 'Jobsworth' who is unprepared to install it other than precisely in accordance with manufacturer's (unnecessary, in this case) 'recommendations'!

The CCU is the large square MK type with an integrated outlet socket. However, the outlet socket never gets used because of its proximity to the cooker. I could fit one of those outlet socket inserts that prevent it from being used inadvertently.

As eric has said, those inserts are not desirable. However, strictly speaking, use of one would not solve the problem, anyway - since, although it might stop the socket being used 'inadvertently', it would not stop it being used at all.

The point is that the diversity calculations say that a 32A MCB would be OK if the circuit didn't have a socket, but that with a socket (whether used or not), it would theoretically have to be a little over 32A - hence, if you wanted to be strictly compliant with the guidance, 40A.

You basically have three options - (a) change the CCU for one without a socket, and stick with your 32A MCB, (b) keep the existing CCU and upgrade MCB to 40A, or (c) decide to exercise discretion and go slightly beyond the diversity guidelines (since that's all they are) and keep your existing CCU and MCB. In all three cases, the existing 6mm² cable should be OK. If you were tempted by (c), bear in mind that although you may be confident that you will never use the socket, a subsequent owner of the house might (although the 'worst' that would then happen would be that the MCB would trip).

Kind Regards, John