Cooker Circuits Diversity, 15kW load, 32A circuit breaker.
Cooker Circuits Diversity, 15kW load, 32A circuit breaker.
Cooker circuits for domestic properties. Protective device, cable size, and what can be connected to the end of it.
In virtually all cases, a 32A MCB and 4mm² cable is suitable for cooking devices up to 15kW.
For connecting to the appliance(s), either 4mm² or 2.5mm² H07RN-F flex depending on the connected load.
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Hi John, thank you for a great video. I currently have a 6mm cable between blockwork and dot and dab plasterboard from the consumer (32amp fuse) unit going to a 9.8kwh cooker (with cooker switch and connector box in between). Its been there since the flat was built are you saying that this is not a preferred method? the rest of the flat is the same although 2.5mm cable… many thanks in advance.
Hi. Great video. Have you ever seen an induction hob connected to two 16A MCBs? We have a hob that is getting an E8 22 error after a few minutes of cooking. Would it be better to replace the 16A with a 32A breaker?
Pah a cooker in 4m cable I would nt do it / soon be using wet strung
Brilliant. I know the theory of electricity but am no electrician. Built in oven is kaput, wife would like the gas hob replaced as well. Does this mean ripping up the kitchen to provide all the extra power? This video answered all my questions. Nice wee bit of humour too.
This guy explains things brilliantly! Does anybody know if he’s done a video on a 13amp cookers, hobs? Cheers
Hi John,
I’m a new apprentice/improver, and enjoying your videos, thanks for making them.
I asked the electrician’s at my employer about 4mm cooker supplies. They were of an opposite opinion – that cooker supplies should even be on a 10mm!
This is on account of, as soon as the cable goes into a loft, god knows it’ll be buried in insulation, going through walls, enclosed in oval conduit conduit in walls, or worse half the time – due to poor original installations.
Is it the case that for a 4mm cooker supply, the reference method has to be C, literally at every point of the cable run? Which is often unrealistic in many properties. If the cable goes down through oval conduit in a wall, does that mean straight away the cable loses its ability to lose heat and a 6mm immediately becomes necessary.
Cheers, grateful for your videos, they are very useful to keep pushing my learning.
Matt
A 4mm cable with a 32A mcb at CU. A hob and oven to be connected.
A hob can be connected directly to the 4mm cable. Fine. As you said, a 3kW oven will never draw more than about 13A, unless in a fault situation. So, the oven can be plugged into a 15A fuseless round pin plug and socket which is off the 4mm cable, behind the oven. 15A round pin plugs are still legal on radials on directly on a final ring circuit (can be on a radial spur circuit off a final ring). Using a normal square pin 13A plug gives an inaccessible fuse. Fuses ideally should not be inaccessible.
Soo why Electric shower needs a 10mm2 cable if it’s only 10kW ?
Does this still hold true for modern induction hobs, which can pull their full 32a load through just two burners?
For me, this is the best site for electrical know how. I very much appreciate your knowledgeable, helpful posts. First class & very thorough👍
Just about to start a kitchen renovation, your videos have literally put me at ease and I now have a great understanding of the work that will be needed to be done and how it can be done. Fantastic!!
I just watched your video my brother just had new kitchen fitted I don’t know if he had 4mm or 6mm had a 32 mcb . Is wife had delivered a hob and oven one was 2300w and other was 600 he phoned the electrician he said couldn’t put both on that circuit the units had felx on but said no plud so had to be hard wired was he right to. Say the both can’t go on that circuit after watching your video I think he was wrong?
Very informarive video, no need to waste money on larger cables for 2 MCB’s =).
Thanks,
Having just installed an induction hob to replace my gas hob and had to run a new cable for it, am quite happy I used 6mm sqr. Cable is run in trunking between brick wall as this was the only way to get power to it. Very happy it won’t be heating the wall up. I do have cavity wall insulation though so needed to uprate the cable.
Exactly what I need to know. thank you. Excellent explanation!
Amazing! Thanks for sharing this!
Would 8 AWG Romex imported from North America work for powering a UK cooker? Quite obviously, I am looking at this from the eyes of a United States citizenship, and thus the American way of wiring in electrical systems for use in kitchens.
Thankyou for the clear explanation and break down of the explanation into simple steps. The hidden humour of cleaning behind a 20 year cooker made me chuckle too.
Great, very informative. Thank you.
Really useful John, thanks.
thx for your videos I find them very informative and strangely therapeutic:). I appreciate this one is 2yrs old but
could you confirm something for me? I have 6mm cable on 32A mcb feeding induction hob. Disregarding zs and voltdrop etc the cable is currently ref C clipped direct (cable rating 46A). 1meter of cable clipped to wall drops out of cu to underfloor this is all good. However, IF I were to place this 1mtr cable drop into plastic trunking with another cable (e.g. oven) for physical protection am I right in thinking correction factor grouping for 2 circuits would increase required cable rating to (32Amcb/ .8 cg) = 40A and then from cable rating table ref type B I would actually a need 10mm cable (52A) because 6mm cable is only 38A?
I know this is only theoretical but is this actually the impact of adding a 1mtr piece of trunking to a circuit?
How much difference does the common 30 amp cooker circuit and mcb make?
Heating up water & what not, its called cooking JW.😄😄😄
Interesting that you consider "six millimetres squared" and "six square millimetres" to be equivalent. I’d interpret the former as "[six millimetres] squared", ie 36 square millimetres. It becomes more obvious if you try to visualise "2 metres squared"!
How is 2.5 ok for short circuit protection on a 32 amp breaker. Have you a video on this subject ? Thanks
Something here confusing me; potential to draw 61A on a 32 breaker.. what if the twin ovens and all four hobs are in use for a dinner party.. thad’s be the full 60A on a 32A breaker – or are we assuming no-one would ever use both ovens and all four hobs simultaneously?
Hi John please explain 2x 4 ring induction hobs side by side and 2x ovens side by side as I have big family want to install in my new kitchen
16:30 Can you please help me? I have been searching in the 18the Ed and On-Site about the flexible cable but all I can find is the " 521.9 (Selection and Erection of Wiring Systems) Equipment that is intended to be moved in use shall be connected by flexible cables." And of cource in Definitions but that’s a bit useless.
Should I use Table 4E2A 3 core 4mm2?
Thanks
Thank you so much for this video. I was looking to get my dual fuel range cooker replaced with a fully electic one so I wanted to get my head round what was needed before getting an electrician to quote. I started looking at cookers online and they were quoting max powers of 15kw but only needing 32A breaker etc which just did not add up from my basic understanding so thank you very much for explaining.
When choosing the flex cable for the appliance from a outlet plate for a hob or built in oven would you use the same diversity , the first 10amp then 30% of remaining load .
This has answered a question I’ve long wondered about. You’re a champion, thankyou!
Is it safe to put a 25A induction hob into a standard (non kitchen) 32A ring main? The issue being that the ring wire is probably the regular 2.5mm cable running in standard UK socket ring _with no other device on that particular circuit_.
I hear that this is doubled as it goes both ways on the ring.
The device power is rated at 7000W or 1500W/2000W per ring. It’s extremely unlikely that more than 2 rings will be used simultaneously.
I just wonder if it will risk overheating the common 2.5mm cable. The power cable for the device states 25A. And had 2 visible wires for live (red + black).
It’s been difficult to understand whether 25A will be safe for intents and purposes on a 2.5mm non-kitchen 32A ring main (albeit not regulation).
Dont think theres a lot of diversity on cookers my missis has the oven and all 4 rings on the hob flat out lol
It’s better to get three phase oven and have the three phase electrical wiring.
top video the whole of the uk needs to protect this man!!
manufacturers of range cookers (10KW) sometimes they ask us to use 10mm cable, what should we do?
Why do manufacturers put fuse ratings on the manual that exceed these calculations, a Smeg double oven 5 ring induction hob states a 43a fuse?
Thanks again, John. Not the first time you’ve saved me money and educated me.
It’s also been ingrained in my head to use 1.5mm T&E lighting cable….1.0mm is fine with all the LED lamps now available.
I being from the states run 50amps 240 volts 12,000watts (6awg/4mm) and use 1inch conduit for future upgrades
I feel i should donate you some beer port or wine for Christmas. I have learnt so much from you for free. I would happily donate to the J Ward Christmas beverage fund
I recently bought a range cooker 13.2 kW. Manufacture’s book says 40A fuse and 3x6mm cable. I changed the mcb from 32 to 40 on the CU and connected using 6mm to the cooker circuit. Is it alright or the MCB should be bigger?
What happens if the cooker circuit is on a 6mm cable but I would use 10mm to connect the cooker to the cooker outlet?
My inlaws are getting a new large range style cooker thats induction and is about 15.5 kw potentially.
I believe this is on a 6mm cable and a 32a mcb (although) im yet to check so this video has eased my fears for them somewhat
So all those installs with 6mm2 fitted with method C can just put a 40A MCB on. Which isn’t all that useful but does allow for a very fat induction hob+oven setup to be installed. That does mean that you can turn on absolutely everything with no danger of tripping the breaker (in theory this could happen with hob+oven on ful blast, although clearly in practice this just about never happens otherwise there would be a lot more grumbling about 32A MCBs.
It will also save something like 1.2kWh/yr in reduced losses for a 10m cable run (assuming half an hour a day of cooking at 5kW on average), where upgrading from 4mm2 to 6mm2 causes losses to go down from ~21W to ~14W. So that would take a while to pay for the extra copper.
This calculation is more significant for EV chargers which typically run at 7kW continuous for an hours a day on average, and can often be a quite a long run. In my case (25m run) the difference in cost between 10mm2 and 6mm2 is paid for in improved efficiency after 6 years. That’s a sensible option IMHO.
Whats your view on a 6mm 32A circuit with spur from the back of the CCU done in 2.5mm to another (single) socket?
Exactly what I wanted to know. I’m a time served installation electrician with 40 years in the game and although I don’t do much domestic I always thought a cooker switch was supplied with a minimum of 6mm. As John mentions this is a hangover from the old rewirable fuse ratings. Excellent explanation proving you’re never too old to learn but I’d probably still run 6mm over any kind of distance just in case of containment or lagging etc or maybe they wanted some sort of unusually high rating oven. Saying that have you seen the price of 6mm T&E recently? LORD. It’s very tempting to do in 4mm but it feels so wrong.
Eloquently and clearly elucidated as always.
I am thinking of buying induction hob..manual states it’s 9000kw/ 40amp. I have got 32rcd for hob nothing else connected to it. Would I need bigger wire to replace the original 32rcd for higher one..confused 🤔
Oh my god I wish I had seen this before so helpful and reassuring love your matter of fact tone and the clear and concise math
They are NOT the same!!! My oven acutally uses a max of 25A (based on max kw) but the hob max is nearer to 36A (Induction Hob.) That is way different to a normal 32/40A cooker. I would rather play it safe as I have turned everything on at once when cooking a large meal for family/friends. Two circuits, one to oven, one to hob.
EDIT: In my last premises I’ve already had one cooker go up in flames due to this 60+/32A crap. I was using everything and the MCB failed to trip. Then it was not fun (I know it’s the MCB’s fault.) But never again. I always demand max load protected for the cable.
Strangely enough It’s also why I despise rings, if they break that 32A is useless. Radials are way safer and easier to fix.