Replacing a gas hob with electric

We have 5 ring gas hob at the moment. It’s quite large (720mm x 560mm, though I’m not sure how big the hole is underneath), and it’s not actually that close to the double oven that’s built into the units. The oven takes it’s power from a socket that’s actually behind the oven, on the wall at the back of the unit.

We’re about to have our gas boiler replaced with any air source heat pump, which means the gas hob will be the only thing using gas, so we could swap out the gas hob for electric, cap the gas off and save on standing charges

How complex will it be to do this? Does an electric hob require a specific power supply like the oven? Had anyone done this or had it done? Any constructive advice is most welcome

Edit: i suppose a photo may help understand the layout

We got a cheap lower powered induction hob that runs of a normal supply (socket hidden below worktop level). If you actually use 5 rings at once, you’ll probably want a higher powered hob that needs a proper supply. We only ever use two of ours at once, and have had no issues.

I’m following this as I’m also considering a ASHP and will have the same dilemma. Historically, I’ve always preferred a gas hob but I’m sure things have moved on.

That’s huge. Replacement will probably need an electrician.

Nice kitchen.

Oh, barring having to give away some pans etc, no downsides of leaving gas behind really.

We’ve had an induction hob for the last 20 years. Fantastic. Pretty much instant heat, cleans with a quick wipe and has never had any issues. I didn’t install it but as far as I can see its running on a separate supply.

Firstly get induction.

This may not be relevant but could give you an idea for solutions.

We had a subtly different problem. We had a hole (in granite) that was too big for new 2 ring induction hobs and too small for 4. Getting the hole enlarged is not really possible.

Eventually a friend came up with a great idea. He had a thin sheet of aluminum cut, big enough to overlap the granite with a cutout exactly the right size for the 2 ring hob.

Looks great, perfect solution for our issue.

https://photos.app.goo.gl/1TAAMUZFGuL5J2VP8

No idea about the electrics

Electric hobs tend to need a dedicated supply due to their electric load. This will need an isolator above the counter and an outlet under for the hob to be terminated into. You generally won’t get away with a 13a plug outlet.

https://www.mybuilder.com/questions/v/14870/induction-hob-at-7-2kw-30a-what-rewiring-will-be-required

Not impossible but could be a ball ache to wire back to your fuse board/consumer unit and also to install the isolator on the tiled surface.

Then you’ve the cost of your hob.

I’d not bother as gas is so much better to cook on, and is cheaper than electricity too.

You haven’t said how your house is wired, ring or radial or a mix of the two and whether you have an up to date distribution board.

A assuming a modern distribution board and radial for high load you check there’s eough load capacity left on one of the differential breakers on the board and add a 32A breaker to that. If not eough capacity left on any of the differential breakers add one and a 32A  breaker then run a 6mm2 cable to the presumably induction hob. You’l need a junction box for the connection.

I prefer leccy because even top chefs use induction on their TV shows and why live in gas and fume polluted air.

You’ll need a local isolator to comply with BS7671 Electrical regulations. And installing a new circuit requires an electrical installation certificate, not something that your average handy man is competent nor authorised to complete or issue.

You can do it like Edukator says above as long as you don’t plan on moving anytime soon.

You haven’t said how your house is wired, ring or radial or a mix of the two and whether you have an up to date distribution board.

well that’s partly because I didn’t realise it mattered, I’m nott an expert hence asking questions. It’s rings not radial in the main, and (having had to take this photo for the heat pump install just this morning) I can see there’s a free slot as the electric shower was removed. It does though already sound like this is not at task we should tackle in isolation, rather as part of a kitchen revamp

You’ll need a local isolator to comply with BS7671 Electrical regulations

I’d prefer to do things properly, but it occurs to me that having the isolator for the electric oven rendered inaccessible by fitting the oven in front of it means this probably wasn’t done to standard in the first place. Can’t isolate the electric for the oven without removing the oven (or using the breaker board I suppose)

The oven takes it’s power from a socket that’s actually behind the oven, on the wall at the back of the unit.

Is that a double oven I spy in the pic? If so it is very unlikely to safe to use on a 13a plug top, most double ovens I’ve fitted over the years are more like 30a, like the one in the link.

https://ao.com/product/u2gch7an0b-neff-n50-electric-double-oven-stainless-steel-70388-48.aspx

Also your fuse board/consumer unit is full so no spare capacity. It’d probably need replacing to allow an extra breaker to be installed, which would be more expense.

I would recommend that you get an electrician in to carry our an Electrical Installation Condition Reports (EICR), especially with that oven. They could then advise on a cost for the hob supply too.

I’ve got gas hobs at home and used induction hobs a lot whilst working away.

The only drawback is I like to pick the pan up and toss the contents, or shake it around on the hob.

Fine doing that with a big cast iron wok on a gas hob with a huge burner.

Doesn’t work so well on an induction hob as the heat turns off instantly and I was paranoid about smashing the glass.

I’d probably still go with induction though if I was getting rid of the boiler as well.

The shower breaker in the pic is 40A and you only need 32A So that works.

What doesn’t add up is just one 100A differential breaker for all those circuits which add up to much more.

In this part of the world that’s not good practice.

Just a FYI about the gas, you need the meter to be removed by your supplier which stops the standing charge. You can then pay to get the service disconnected at the main in the street, or that would be done automatically after 9-12 months from the meter being removed.

Gas Safe engineer does the pipe work from the meter to the cooker.

Is that a double oven I spy in the pic? If so it is very unlikely to safe to use on a 13a plug top, most double ovens I’ve fitted over the years are more like 30a, like the one in the link.

It is, iirc it’s not running on a 13a socket though, it has the “proper” connection, just tucked away where it’s not accessible

What doesn’t add up is just one 100A differential breaker for all those circuits which add up to much more.

In this part of the world that’s not good practice.

Not here either but that was all there when we bought the place. I’m half expecting the electricity people to come back and say we’re not allowed to install the heat pump until it’s rectified, but they may not.

you need the meter to be removed by your supplier which stops the standing charge

Octopus asked if i wanted the supply capped and the meter removed when they install the ASHP. As we have the gas hob, it needs to stay for now

The shower breaker in the pic is 40A and you only need 32A So that works

You must have special vision to see what size of shower he has. My shower is 8.5kW and needs a 40a breaker. And I’d say that 8.5 is about average in size.

Get a spark in, better than some Internet diy enthusiast.

As an old plumber friend once said, “mess with plumbing, you get wet, mess with electricity and you get dead”

Just to let you know I’m an ex spark although technically I still am a spark as I keep my grade card up to date.

Plenty of houses only have a 60a main fuse, even when they have a 100a fuse carrier, not easy to check either without cutting the tags off.

You must have special vision to see what size of shower he has.

The electric shower went some years ago, but the labelled breaker that it was connected to is clearly marked as 40a

If we go ahead with this then I’ll definitely get someone competent in, but as always STW is proving a great place to understand the complexities i hadn’t considered and this what questions I’ll need to ask

It’s a 40A breaker with “shower” written under it. No special vission needed.

Given that you’re getting a heat pump, electric hob and no doubt an EV before long, that board needs replacing with one with more slots and at least three 100A diiferential breakers for the house and another for the future car.

A bit beyond tryi ng to claim “it was always like that” 😋

As for professional sparks, my parents had some electrical work done when they had a new boiler fitted. I had a look and found their lighting ring was wired without a differential breaker. All signed off but lethal.

Doesn’t work so well on an induction hob as the heat turns off instantly

That’s not actually true – with induction the heat is generated by the pan itself – so if you remove a heavy pan (i.e. cast iron) from the hob the heat will not disappear as quickly as it would it you’re using a lighter (thin) pan.
But yes you want to watch the glass a bit!

 You generally won’t get away with a 13a plug outlet.

There are lots of 13amp induction hobs available – they’re not ideal but they are OK for some.

Changing from a gas hob to induction was one of my better decisions – and that’s before I realised about the emissions gas hobs pump into your house!
I’d never go back.

The only work happening for sure is the heat pump, we’re considering a new hob but an EV is not on the cards as yet.  If that means redoing the electric distribution board then I’ve no issues doing that

100 amp main switch is standard. The other circuits can add up to more than 100A because an allowance is made in the regs. for electric diversity i.e the fact that not everything is loaded up and turned on at the same time. You will almost certainly need a new dedicated supply for the new hob although this depends on the power of the new hob. Your board has no RCD protection and no space for any additional circuits. Time for an upgrade with a new board with latest RCBO breakers. This is definitely a job for an electrician to advise you on. I’m qualified and have 18th edition regs. certificate.

We switched from a gas hob to induction a few years ago, I wouldn’t go back to gas. Induction is just as good to cook on (but make sure you get a good induction hob, some cheapo low powered thing will probably be awful), but benefits from not generatijg any condensation or other combustion by products, quicker to heat any given pan, easier to clean, looks nicer (this is subjective I guess).

Everyone else has covered the electrical side of things.

“You’ll need a local isolator to comply with BS7671 Electrical regulations “

No you dont, but having one is beneficial. BS7671 says there must be a form of isolation available. The circuit breaker is sufficient for that.

“ I can see there’s a free slot as the electric shower was removed.”

But, unfortunatley for you, no way could that be used by a competent electrician. What you’ve got there is at least 20, probably 30 years old, and really needs upgrading. It will carry on fine for many more years as it is, but no one can add to it without some work. Firstly, you need a Type A RCD for the induction hob. You currently have an ‘upfront RCD’ which will take out all of your circuits if there is a fault. It isnt marked, but is likely to be a Type AC, which we dont use anymore. The circuit breaker for the shower is not made by MK (same as the two GE ones), so that is frowned upon now, all breakers must be made for the consumer unit. Its a plastic consumer unit, which in itself isnt too bad, but they have been metal now for 5 years+, and most sparkies will not want to connect into an old plastic one, even if they could find the correct circuit breakers to make it good.
What you need is a new consumer unit, preferably with a lot of RCBOs in it, rather than 2 RCDs (but they are still available, and OK to fit). You’ll need a new circuit to supply the hob, 6mm twin and earth cable is usually suitable. Can the vable be ran in from the wall at the back of the kitchen, if so, that’d be pretty easy, put an isolator switch in one of the cupboards, and run the hob cable from there.
The people doing the ASHP will need to fit a new consumer unit to supply the HP and its ancillaries, I doubt they will run it through the existing upfront RCD (they shouldnt), so they will tap into the supply cable from the meter to supply their consumer unit. Possibly now is the time to get it all sorted, and get their electrician to give you a price to put it all in one consumer unit?
What is the one at the top – storage heaters? If so, that can go when the ASHP is fitted, and a modern 12 way consumer unit could be fitted in that space. It looks a fairly easy swap, all cables accessible, there wont be any faults on the existing wiring, as the RCD would be tripping, so half a days work to swap it out.

Alanl, I don’t see any RCD protection on the board ?

The rcd is a separate unit between the lower board and the meter

The upper board I’m guessing was added when the house was extended, I’ve worked out what most of the breakers do and labelled them but there’s one in there that’s still unlabelled. It’s not been a problem to date though

The ASHP is from octopus and their fixed price is “all-in” so I’m hoping that means they’re replace the kit if needed. If not then we can consider it as a separate job to the ASHP.

Anyone local to marple fancy quoting?

Yes I see it now…not on the board

lighting ring was wired without a differential breaker

Is this satire?

No you dont, but having one is beneficial. BS7671 says there must be a form of isolation available. The circuit breaker is sufficient for that.

I think you’re being a bit fast and loose in your interpretation of ‘local’ you shouldn’t have to go looking for the isolator in a cupboard under the stairs in another room to locally isolate an under counter appliance. The clue is in the name ‘local’

I’ll stress again, get a spark in, preferably one with a JIB/SJIB skills card and working for a company affiliated with the NICEIC. Electrician is not a protected term but to get a JIB/SJIB you do need to show competency by completing courses and working in the industry for a period of time.

I don’t do satire, didn’thurt. 1000s of posts, no satire, even if you think it sounds like satire non was intended.

Thankfully breaker boards are in a cupboard off the kitchen so quite close by

“No you dont, but having one is beneficial. BS7671 says there must be a form of isolation available. The circuit breaker is sufficient for that.”
“ I think you’re being a bit fast and loose in your interpretation of ‘local’ you shouldn’t have to go looking for the isolator in a cupboard under the stairs in another room to locally isolate an under counter appliance. The clue is in the name ‘local’ “

There is no call for ‘local’ isolation, or switching in BS7671.
Page 25, 132.10 Disconnecting devices: – ‘Disconnecting devices shall be provided.. to permit switching and / or isolation…
Page 124 462.1.201 …a main switch or circuit breaker shall be provided… as a means of switching … and isolation.

There is no reference to local isolation. As I said, it is usually done, but it isnt a requirement of BS7671.With the common fitment of isolator switches inside cupboards now, they are not particularly accessible, and are of no use for emergency use, for that, a specific emergency switch MUST be fitted if it is required. Many switches for cookers are not suitable for isolation anyway, as they cannot be locked off, so safe isolation must be done at the consumer unit, on either the main switch or the circuit breaker, depending on the supply earthing.

We had a 32 amp connection put in for our 5 ring induction hob, Which looks a similar size to yours. it can draw a lot of power when running flat out.

“I’ll stress again, get a spark in, preferably one with a JIB/SJIB skills card and working for a company affiliated with the NICEIC. “

Yes, to change a consumer unit, or put in a new circuit they will need to submit a Part P certificate, however, there are other Governing bodies than the NICEIC. In fact I’d say NICEIC are the worst. A NICEIC affilated Company only has to have one person in the Company as a qualified electrician. They could have 100 labourers working for them, so long as the one qualified person signs the certificates, the NICEIC are not bothered.
NAPIT are another governing body, they are better in that each person must go through their verification every year. There are 2 others but they are so small that people havent heard of them.
As for JIB/SJIB, there are not many domestic electricians who bother with the JIB card, and their stupid requirements. JIB cards are more of a site requirement, and give no more assurance than saying a Company is a member of the NICEIC. The JIB do not investigate shoddy work (and it is rare for NICEIC to either), they are only there to take the £150 or so every 3 years when the card is renewed. You could have killed 50 people in the last year, but so long as you show them your apprenticeship papers, they will give you a card when you hand over the money.

That sounds pretty slanderous on the NICEIC there. I’m in Scotland and we don’t have Part P, we have Scottish building regs instead. And we can only use NICEIC or SELECT. And I’d say NICEIC are marginally the better of the two IME. But definitely better than someone without either affiliation.

@alanl

Not all isolations are for maintenance, sometimes you might want to isolate an appliance that is faulty.

Heaven forbid but……

Good luck defending why you never installed a local isolator on an electric hob in a court of law.

We refitted our kitchen a couple of years ago. There was a 6mm2 supply from 32a RCBO in the plastic consumer unit to the oven isolator on the wall. From this, a 6mm2 cable ran to the old oven, and a 2.5mm2 cable ran to a 13a plug under the old gas hob for the ignition circuit.

I had a plumber disconnect and cap the gas.

Once the plasterboard and tiles were removed, I replaced the 2.5mm2 cable with 6mm2 to a new outlet for connecting the induction hob. I can’t recall the exact figures, but the diversity calculation showed that the 32à RCBO and the 6mm2 cable were all suitable for the theoretical load.

This year.we had a new shower fitted, and it cost £650 for a new metal bodied consumer unit, plus £120+vat for certification.

With regard to the induction hob, I consider that I was modifying an existing circuit, not installing a new one. The RCBO, initial 6mm2 cable run, isolator in the kitchen,and cable to the oven remained the same.

@TroutWrestler for the win. All fine IME.

Diversity for cookers is explained here:

Essentially you allow 100% of the first 10 amps then 30% for the remainder