Induction cooker circuit wiring

SashikoStitcher

This is just a warning to anyone thinking of getting an induction hob or range cooker. 

Our cooker circuit, which was installed 6 years ago as part of a kitchen refit, has 6mm cabling. I understand this is the standard size for most cooker circuits. Our dual fuel Rangemaster has been running on it no problem for years. 

I ordered a new induction-top Range (Stoves brand) but only discovered after delivery that it needs 10mm cabling to be connected. 

It’s not an easy job to replace the 6mm with 10mm as the 10mm is so thick it can’t just be pulled through the same channels. We’re looking at huge expense and disruption to do it, so the new cooker has to go back. 

The one I chose does have particularly high power rating but the retailer says that there are no inductions that work with 6mm. 

By the way, my electrician wanted to speak to Stoves customer service to discuss the spec but they are completely uncontactable- website says “speak to our friendly team” but we’ve been trying for 3 days and the line cuts off with “your call cannot be completed, please try later” after a recorded message.  They have no email and don’t reply to their online enquiry form.  

ThisIsWeird

SashikoStitcher said:

This is just a warning to anyone thinking of getting an induction hob or range cooker.

Our cooker circuit, which was installed 6 years ago as part of a kitchen refit, has 6mm cabling. I understand this is the standard size for most cooker circuits. Our dual fuel Rangemaster has been running on it no problem for years.

I ordered a new induction-top Range (Stoves brand) but only discovered after delivery that it needs 10mm cabling to be connected.

It’s not an easy job to replace the 6mm with 10mm as the 10mm is so thick it can’t just be pulled through the same channels. We’re looking at huge expense and disruption to do it, so the new cooker has to go back.

The one I chose does have particularly high power rating but the retailer says that there are no inductions that work with 6mm.

By the way, my electrician wanted to speak to Stoves customer service to discuss the spec but they are completely uncontactable- website says “speak to our friendly team” but we’ve been trying for 3 days and the line cuts off with “your call cannot be completed, please try later” after a recorded message.  They have no email and don’t reply to their online enquiry form.  

Interesting, as I'm exploring that same issue myself at the mo'. I don't think your sparky is completely right.

I'm after a physically larger indie hob, so looked initially at 900mm wide jobbies with 5 'rings'. All of these were rated at over 10kW, so it was clear that my existing 6mm cable was not going to be good enough. I could run a 10mm alternative, but didn't really want to.

So, I'm now looking at 750mm-wide hobs with only 4 plates, and these are typically around the 7.5kW rating, so should be fine with 6mm and 32A. (In practice, it'll almost certainly be drawing a lot less than this max total - unlike electric showers which do)

What's more, many indie hobs have adjustable power ratings that can be set on or after installation using a menu. They can, for example, limit each plate to, say, a 2kW max, or whatever your existing supply can provide. You could retain one 'ring' as a 'max heat' one for frying and searing, but reduce the others down to a suitable max amount.

SashikoStitcher

Thanks. We’re limited to ranges with induction tops rather than a standalone hob, retailer says nothing exists that can be safely wired to 6mm. 

I’d like to discuss exactly what you describe above with the manufacturer, but they are totally uncontactable. 

ThisIsWeird

Ah, I see - sorry, missed that bit.

Ok, this is weird, but I've also been looking into these, too, for a local yoof club! A model I'd short-listed was the Belling 90Ei. I'll need to confirm, but I 'think' this is 6mm-capable.

When you think about, tho', a range cooker has all the oven elements to cater for as well, so I'm not at all surprised if it needs 10mm and 40A MCB.

Edit: This has the spec in the listing, and it says 'Power: 32A'. That 'should' be 6mm doable - but sparky would need to confirm. https://www.ebay.co.uk/itm/204235315561?

DullGreyGuy

SashikoStitcher said:
Our cooker circuit, which was installed 6 years ago as part of a kitchen refit, has 6mm cabling. I understand this is the standard size for most cooker circuits. 

It would be a standard size for electric ovens and gas hobs but not for anything with an electric hob and ovens. Ours had 10mm installed despite having dual fuel as it was anticipated we'd move to all electric in time. 

SashikoStitcher said:

Thanks. We’re limited to ranges with induction tops rather than a standalone hob, retailer says nothing exists that can be safely wired to 6mm. 

I’d like to discuss exactly what you describe above with the manufacturer, but they are totally uncontactable. 

In principle something could be 32amp or less, and the older Stove ranges were, but my preferred retailer shows that Stove have updated their models not too long ago and they are now all over 32amp like the other brands they stock. Similarly they dont have power management like some hobs do so you cannot hamstring them to run on a lower power load.

Your only options are to look at duel fuels, buy an old Stove range that runs on the lower power if anyone is holding stock or replace the cable. AO is a firm that holds stock rather than just ordering from the manufacturer; they do have at least 1 older Stove Range that will run on 32amp

SashikoStitcher

thanks @DullGreyGuy. Now I come to think of it, the 6mm cooker circuit was not installed new when we had our kitchen done in 2018, it was there already and just signed off as suitable for the range we had (dual fuel). Not sure when the previous owners would have put it in. 

So would you say that anyone getting a new kitchen these days would automatically get 10mm cabling? 

I’m actually quite interested in whether it was reasonable of the retailer and manufacturer not to highlight the 10mm requirement in their sales material. The less common 10mm circuits are, the more sense it would make to warn that one is required/advise people to consult an electrician before purchase. 

That’s a bit different to the standard advice to get a professional to install it, which I  followed. 

SashikoStitcher

PS In your opinion would anything rated 32A run on 6mm, or is it more complicated than that? 

I ask as I can see several induction ranges on my retailer’s website that say 32A, eg this one, which is a Stoves. 

DullGreyGuy

SashikoStitcher said:

thanks DullGreyGuy. Now I come to think of it, the 6mm cooker circuit was not installed new when we had our kitchen done in 2018, it was there already and just signed off as suitable for the range we had (dual fuel). Not sure when the previous owners would have put it in. 

So would you say that anyone getting a new kitchen these days would automatically get 10mm cabling? 

I’m actually quite interested in whether it was reasonable of the retailer and manufacturer not to highlight the 10mm requirement in their sales material. The less common 10mm circuits are, the more sense it would make to warn that one is required/advise people to consult an electrician before purchase. 

That’s a bit different to the standard advice to get a professional to install it, which I  followed. 

I wouldn't say its "automatically" as some people say they will use gas until they die, many will be in your situation or using existing wiring and so if installing a dual fuel they'll just continue using the old wiring as you now say you did. Some will want a separate hob and ovens so only the hob 

Retailers/manufacturers are only going to tell you what amp fuse you need, they aren't going to want to have to keep up to date with every countries electrical safety standards. Secondly, cable size required can depend on length, encasement, conduit size etc and as retailers dont want to do a site visit to check all these things on each and every query of a sale they have they will stay silent and tell you to ask your electrician.

SashikoStitcher said:

PS In your opinion would anything rated 32A run on 6mm, or is it more complicated than that? 

I ask as I can see several induction ranges on my retailer’s website that say 32A, eg this one, which is a Stoves. 

As above, its more complicated than that but in most cases 6mm is appropriate for 32A however you should check with your electrician who can confirm 

This would imply the cooker is under 7.5kW -v- their current models that are all 15kW. It may be enough for your needs but having had the misfortune of using a friend's 13amp 4 burner induction hob it was terrible, could only realistically use 2 hobs at the same time unless it was "keep warm only". 

Our hob is over 7.5kW without any ovens and it can support all 4 hobs on "full" but it won't support 1 hob on boost and the other 3 on "full". Clearly having ovens and presumably at least a 5th ring and 7.5kW the max you can have going at the same time will be less. 

SashikoStitcher

Thanks. 

It’s a UK manufacturer, so not sure there’s any issue about keeping up with different countries’ standards. That one I screen shotted with the 32A fuse says “connected load 15530W” at the top, so it’s much more than 7.5KW. 

I’m slightly bemused at the idea that people just have an electrician. I can book one to come and install an appliance for me, but I don’t have one on speed dial that I can just call to chat about potential cooker purchases. 

FreeBear

DullGreyGuy said: Retailers/manufacturers are only going to tell you what amp fuse you need, they aren't going to want to have to keep up to date with every countries electrical safety standards. Secondly, cable size required can depend on length, encasement, conduit size etc

For short runs, 6mm² may be suitable. Go any distance and embed the cable in a heavily insulated wall, you may need 10mm² or even 16mm². Only an electrician can determine what size is needed after looking at the property.

DullGreyGuy

SashikoStitcher said:

Thanks. 

It’s a UK manufacturer, so not sure there’s any issue about keeping up with different countries’ standards. That one I screen shotted with the 32A fuse says “connected load 15530W” at the top, so it’s much more than 7.5KW. 

I’m slightly bemused at the idea that people just have an electrician. I can book one to come and install an appliance for me, but I don’t have one on speed dial that I can just call to chat about potential cooker purchases. 

They dont only sell in the UK which could create a liability if they said 6mm is fine but in another country their regs require it to be a 10mm cable. 

You simply can't draw 15.5kW on a 32amp fuse with the UK's 230v single phase power supply so one of those numbers is wrong.