Cabling for induction range cooker-a cautionary tale!

[HotCrossBunplease]

I’ve just had a fab new induction range cooker delivered. (Stoves brand)

It was replacing an existing Rangemaster installed 8 years ago as part of a full kitchen refurb. As the wiring was all done carefully and to regulations then, I rashly assumed that the new one could just be wired into the wall where the old one was removed.

Unfortunately my builder has just told me that we only have 6mm cabling from our fuse box (consumer unit) to the cooker circuit. The induction range has a much higher power load than my old gas hob/electric oven one, so I need 10mm cabling. And replacing that is not a 5 minute job as apparently 10mm is so much thicker than the 6mm that it can’t just be pulled through the same route that the 6mm wiring currently goes. He’s given me an electrician to contact to confirm but he’s pretty sure that connecting to the existing 6mm circuit will just trip the fuse.

NB the spec of the new cooker says Max power load 17.97-19.17 KW. Looking at the spec for my old Rangemaster, it was only 7.4 KW, a huge difference.

So my post is for 2 reasons:

1. to warn anyone getting a new cooker, particularly an induction one, to make sure you have the right wiring. I understand that 6mm in cooker circuits is quite common.
2. To ask if anyone else has had to upgrade from 6mm to 10mm and if there are any other issues I need to look out for?

I could send the cooker back but it is so lovely and I have my heart set on induction now ☹️.

Well the bad news is it doesn't really matter in terms of cost because as I said they normally do them for free anyway. But the good news is it is probably one less thing to organise.

Ooh exciting development. Finally got through to Stoves. The guy there confirmed that my range does need the 10mm wiring but any of their other inductions will be fine on 6mm/32A. The one I chose is zoneless, hence the high power, but they do a zoned one that is otherwise identical, so I should be able to get the retailer to swap it for one of those.

Annoyingly I’ll still have to pay a hundred quid to return it as I have unpacked it, so will totally lose out on the saving I make by the non-zoneless being cheaper.

And will be a helluva lot cheaper than the cost of rewiring!

Thanks for the update, hopefully the alternative is in stock!

Sounds like they finally come through for you.

Great news.

It’s interesting that the manufacturer’s advice was completely different to what the retailer said.

Hi OP, 19kW is over 80A, a 10mm cable is not big enough to do this. Make sure you speak to a qualified electrician not just a kitchen fitter. The oven may have two seperate wiring points, as you can't install an 80A electrical appliance from a standard domestic consumer unit. It may flat out not be suitable.

Happy to look at the spec sheet if you have a link.

Just wanted to say thanks for this thread - currently in the middle of a partial rewire and seeing this prompted me to speak to our electrician about whether our existing kitchen wiring (not part of the rewire) would be sufficient for an induction hob when we do the kitchen. Turns out it wouldn't be, so we're having it done now when it will be far easier (and presumably cheaper!) than when we get around to replacing the kitchen.

So thank you 🙏

If you’re happy to spend the money , every circuit can have its own rcd protection built into the ‘fuse’ ( circuit breaker ).
That does away with grouping circuit breakers to belong to one of the two rcd in a typical consumer unit.

OP do you have unused slots in your consumer unit now?
It'll be easier for an electrician to use a blank space to wire in a 10mm cable.

its not just induction hobs needing 10mm that people need to watch out for. The same applies if you were upgrading from a 7kw electric shower to a 10 or 11kw shower.

Ah that’s great to hear that it was helpful, exactly what I intended by posting. Enjoy your new kitchen when you eventually get it!

Yes, I am speaking to an electrician rather than a fitter as we’re not having a new kitchen fitted, just changing the range.

The manufacturer has confirmed today that 10mm is what is required, I can’t imagine they’d make a product that can’t be wired into a domestic kitchen.
Spec was posted upthread.

My understanding is that the key difference between a shower and a cooking appliance is that the shower has to operate on full power at all times to heat the water, whereas a cooker will rarely have every single element drawing full power.

Not sure about the blank spots, will check. Thanks.

When we rewired 4 years ago our sparky laid extra power through to the kitchen, in anticipation of this. He said that in addition to the possibility we'd later have an induction hob, modern ovens were tending towards a greater power use when ovens were just switched on to heat up ovens faster, which could be an issue in the future.

In case anyone is still interested, we’ve had an electrician round who has confirmed that it’s possible to upgrade our wiring to 10mm. It’s a bit fiddly as there are obviously cabinets and tiles in place, but they can get the wire under the floorboards to just outside the kitchen and then they’ll feed it behind some cupboards and put a new isolator switch in a hole at the back of a cupboard, rather than trying to use the existing one on the wall. (Fortunately we have “shabby chic” bare floorboards through all the downstairs so they’re easy to lift.)
So no damage to wall or floor tiles in the kitchen.

Needless to say, it’s not cheap, but the retailer didn’t have any stock of the lower power range that we wanted and we lost our stomach for returning it and buying another one elsewhere and all the faff that would involve.

Electrician said they tend to put in 10mm as standard when new now even if an appliance could run OK on 6mm, for reasons like @BlueMongoose stated above.

However he also confirmed that any appliance that is needs a 32A fuse should be fine on 6mm so it was sod’s law that I picked a ridiculously power-hungry beast. I’m a little bit annoyed at Stoves not highlighting in their sales material for their snazzy new zoneless hob that it needs extra-careful checking with an electrician before buying, but I guess the warning that I wanted to give with this thread is perhaps only applicable in extreme cases.

Electrician can’t fit us in for ten days so in the meantime I am hilariously cooking on this (which we had in the cupboard anyway) and my Instant Pot, while my new purchase lurks disconnected behind me. I refuse to buy an air fryer when I have 4 ovens coming online very soon, so am digging deep into my casserole and pan-frying repertoire!

Ten days will fly by, that range will be worth the wait! (I would have got an airfryer too though. So many things come out better in one than an oven, no matter how snazzy...)

yes it sucks and this is the reason why we stick to current style over substance dual fuel range as adding the necessary extra circuit and cabling would mean major building work.

La la la not listening 😀