Installing an electric cooker?

Can I get some advice?
Just moved house, and have an electric cooker to plug in. It says 10kW on the cooker, I was told it needs a 30A cable.
My supply looks like a regular plug socket, and theres a switch with a light next to it,which works off the 32A cooker circuit on the main fusebox.
Do I fit a 6mm cable to the cooker, and a regular plug (with a bigger fuse)at the other end, and just plug it in?
Or do I need an electrician to install a special box and new fuse in the main fusebox?
Or what?

I make that 40 amp so it cannot go on a conventional plug. It must be hard wired into a separate circuit all the way back to the consumer unit

I am a bit confused by what you are saying – is there a dedicated 32 amp breaker just for the cooker? If so you might have the right circuit just with a the wrong terminal. If it is a seperate circuit then try taking the cover off the outlet. Is it 6 or 10 mm ? or 2.5?

Pics might help

see https://www.youtube.com/watch?v=QQduU8RkjD8 which explains why a 32A circuit is correct for such an electric cooker on the basis that not all elements will be on full at the same time. He also explains what cable or flex is appropriate – often 4mm squared.

There may be a hard wired connection point to connect the cooker to hidden behind a cupboard.

Best to get an electrician to have a look and quote for doing what is needed. You can not connect via a normal plug.

Came across this video when researching similar situation – ended up getting an electrician in.

My cooker is wired the same, however that regular plug socket is not a regular plug socket, its a cooker isolator with a socket attached. The cooker does not plug into the socket, it is hard wired into the back of the face plate with an appropriate rated cable, ie 10mm twin and earth not 6mm.

good call stumpy – not seen those for years but they do still exist

there is a dedicated 32 amp breaker just for the cooker
stumpyjon-does that mean taking the socket off and hardwiring the cooker in its place?when you say faceplate, I dont see anything else that would be it. Maybe there is something behind the cupboard by it
I’ll check for it.but cant switch electric off yet as Im testing the new washingmachine.

-does that mean taking the socket off and hardwiring the cooker in its place?when you say faceplate, I dont see anything else that would be it

No, it would be the size of a double socket or bigger, and have a socket on one side and a single switch labelled ‘Cooker’ on the other.

greybeard, theres nothing like that double socket. I have checked behind the cupboards too

We have a switch labelled cooker to the left of the cooker gap above the worktop (no extra socket though).

When I came to replace the cooker there was a 10mm slightly squared cable coming out if the wall behind the cooker, this wires directly to the back of the cooker.

With yours, there should be a similar wire either in the cooker gap, or either side – though why it would be hidden behind a unit I don’t know.

So with a separate cooker illuminated switch, and a separate Mains circuit in the fusebox labelled 32A cooker, I should expect there to be a big cable there somewhere?

Yep 😁 otherwise what’s the switch connected to.

I have mine set up so there is a switch above the worktop and an outlet below it – when removing the cooker normally you remove the cable but the outlet should still be there

https://www.tlc-direct.co.uk/Images/Products/size_3/CM2177.JPG

should be heat resistant cable really – not grey 2&E should it not?

‘Yep 😁 otherwise what’s the switch connected to.’
only the normal socket sofar….
but I’ll look behind it tomorrow.
but why would you have a spare socket connected to it? And are those regular sockets not safe for over 13 Amps?

The one in our house is like that. It is just an extra socket and a cooker switch in one piece. I guess it means matching size double backplates along the wall.
Big red switch operates cooker and switches to a wire or backplate on the wall behind the cooker.
Socket is just another socket. Handy for the stick blender when making soup as it is right by the cooker but otherwise just a socket.
Similar beast in Screwfix:
https://www.screwfix.com/p/british-general-900-series-45a-2-gang-dp-cooker-switch-13a-dp-switched-socket-white/56392

Edit: the socket does mean that you can plug a lamp in if you want to check that you have isolated the mains before grabbing the large piece of cooker cable to attach it to the cooker.

Yes the cooker switch with an integrated 3 pin socket should have an outlet plate (normally behind the kitchen cupboards) for the cooker supply to terminate into. The cooker must be terminated/hardwired into this outlet plate, you cannot wire it into a 3 pin plug.

If there is a gas connection for the cooker, the outlet plate may not longer be visible after the last kitchen refit.

Electric hobs and cookers need to be supplied separately from the 13 amp socket ring main because they draw more current. A 10kw cooker needs a minimum 10 mm cable run to a dedicated circuit breaker at your consumer unit and locally isolated at a dedicated switch. If in doubt call in a local electrician, it’s high current and there are a few factors to take into account such as the cable run length and good earthing.

Electric hobs and cookers need to be supplied separately from the 13 amp socket ring main because they draw more current

Not always. I have had both hobs and ovens that are less than 13 amp. But in this case its far too high power

A 10kw cooker needs a minimum 10 mm cable run to a dedicated circuit breaker at your consumer unit and locally isolated at a dedicated switch.

No it doesnt.
To stop such ‘urban rumours’ going around, here are the true facts for cookers.
Cookers are allowed a ‘diversity’ rating (as pointed out by timf, not all elements are on at the same time)- the correct way to size the circuit and cable is this – the first 10 amps, plus 30% of the remaining rating, plus 5 amps for the socket.
For a 10kW rated cooker, that works out at a 43 Amp rating (10k/230v).
10A + 30% of 33A + 5A for the socket outlet. = 10 + 9.9 + 5 = 24.5 Amps.
So, if you had one, it could run off a 25 amp circuit breaker. As they are not common, we go to the next size up, which is a 32 amp circuit breaker.
Cable size. For a typical house, where the cable is run in the walls, and in free space between the joists, a 4mm twin and earth cable will be sufficient. However, 6mm T+E is typically used. This is because house electricians dont bother working anything out, and just use a ‘standard’ circuit, so they know it will be OK. Using 6mm T+E makes no practical difference, and will only cost around £5 more to install, and, they will probably have a roll of 6mm in their van, whereas 4mm cable is less common.
A caveat, if the cable runs in any insulation in the house, then the cable may need to be downrated a little, as, when it gets warm through use, it will not be able to radiate that heat away with insulation around it, so, it is possible that 10mm T+E cable has been used to supply the isolator, to allow for the extra heat in the cable.

Now, we have the final connection. Most cooker makers recommend using rubber flex, of the top of my head this is HO5 or HO7 cable. It is very flexible, and has a slightly better heat resistance (to outside sources) than twin and earth cable. This cable needs to be sized to be protected by the circuit breaker. 4mm, 3 core, flexible HO7 cable has a rating of 34 amps. So a 4mm HO7 flex will be sued for the final connection. There is no point going to a bigger cable. Bigger cable (6mm up) is more expensive, not required, harder to terminate, and impossible in many cookers, as the outer sheath is too fat to be gripped by the cookers termination clamp.
So 4mm HO7 or HO5 flex, from the outlet on the wall or adjacent cupboard is all that is required.

good stuff alani – its nice to have someone who actually knows 🙂 Is there not a length part of the load calculation as well? I seem to remember longer runs need bigger cables but that could be old wives tales 🙂

I put 6mm in for my cooker for 12m run with a 4mm heat resistant final connection

Is there not a length part of the load calculation as well?

Yes, there is, but in the typical house, it will not need to be taken into account.
Anything over ~75 metres will need calculating to make sure it complies. A 3 bed house is unlikely to have a cable length for a cooker of over 30 metres, so will easily comply with volt drop, and the resistance of the earth.
Volt drop needs to be less than 5% iirc. The cable has a known resistance value, it can be worked out from its length as to if it will comply.
The same goes for the Earth Fault Loop reading. A test should be made at the end of a circuit, to determine if a fault occurs, can the circuit breaker trip in the required time (0.2 or 0.4 of a second usually). Again, cable length affects this, and the cable should be sized accordingly. If the cable has a very long run (~100 metres), then the cable will need to be sized up, as there is less resistance in larger cables.
But, in houses, it isnt necessary to do any calculations 99.9% of the time.

I do my own electrical work and have a very fussy sparkie who checks it for certification so all my stuff is belt and braces. I’d rather it that way tho

I still cant find an outlet for the cable
It looks like the previous cooker was gas
thanx alanl for that. I saw the video above about diversity
I took the switch cover off, theres some big wires behind there
Is it a requirement for somebody to have an electrical diagram of each house’s wiring? that would be available to the housing society’s contractors etc?
looks like more microwave scrambled eggs on toast, in the snow, this week

Where is the socket that is run off the cooker switch? Is it below worktop level? Its possible that was the outlet but no longer needed with a gas cooker so a socket put on instead. would be odd but possible

yes its below worktop level, as is the sockety beside it, which comes off the fridge switch
I guess if thats the case I will still have 4mm wires there, and it’d be simple to reinstall the cooker