Can i use the 10mm² T+E cable for my Oven AND possible Induction Hob

[NHW]

I put an original post before where I was asking if my newly bought oven would suffice on a 15amp normal plug. There were some 'possibly's' but mainly it was no due to safety.

So i just spent the night with my cousin Routing through a 10mm² 44amp T+E cable from the garage to the kitchen, following existing cabling and going through the upstairs floorboards (it's not actually connected, will get a qualified electrician to do that)

So I believe that this cable can handle upto around 10,500w (44a/240v).

My oven is 3,950w (which is why I upgraded the cable in the first place)

I have no idea how this all works but does that mean I potentially have another 6,000w to 'play with' because I was thinking of changing from gas to an induction cooker and I believe that at some point they will both be running concurrently so hence why I assumed I would have to add up the W, and that both maximum W cannot exceed 10,500.

Sorry if this sounds stupid but just thought I'd check before I go to a sparky so that at least it looks like I understand what I can or cannot upgrade to. Thanks

 

[Adam_151]

You're fine. Diversity for a domestic cooker (hob and oven, either separatly, or as one appliance) is 10A + 30% of the rest (+5A if there is a socket on the cooker switch)

 

[EFLImpudence]

10mm² T&E can carry 64 Amps but you only need 4mm² for a 32A cooker circuit (method C) although everyone uses 6mm² and because of diversity is adequate for 20kW of cooking appliances or 16kW with a socket.

 

[sparkwright]

Not sure why the op thinks 10.0mm2 cable is rated at only 44amps.

 

[ericmark]

The cable rating depends on installation method. There is a PDF chart here to show rating it is common to use a twin cooker connection unit and power two appliances from one supply.

However this depends on the appliance, we expect an appliance to be able to be supplied with a 32 amp supply even when it is only going to use 16 amp, it will need some short circuit protection, clearly you could not use a 400 amp feed, but few seem to state what the upper limit is. Using up to a 45 amp supply has been known, at such not sure should there be an internal fault that the appliance would be protected?

On a forum just the other day some one was saying how there new oven stipulated a supply of between 16 to 20 amp, this would clearly present a problem. I have always wondered why we can't buy a fused connection unit which will take a 16 amp fuse, however in the UK 13 amp seems to be the limit. So we jump in size from a unit which fits in a standard back box, to a massive consumer unit.

There is no good reason why the oven should not have an internal fuse, but they don't, except for microwave ovens.

Looking at it sensibly my cooker has an oven and an induction hob and runs fine on a 32 amp supply and has done for around 10 years without the overload tripping, for 20 years before that we had a cooker with a ceramic hob, which was less economical which also ran on a 32 amp supply without causing the overload to open, so there should be no difference in the supply requirements with the oven and hob combined as to when they are separated, it has always been possible to use more that the overload rating, but not with normal cooking.

One heat area on my induction hob can deliver 3.7 kw into the pan, however other than plain water, that amount of power would simply burn the food, so only half that is normally used, it has a boil/simmer function so one can set the ring to boil then auto reduce to simmer, so in theroy you could put on 4 pans together, but in real life that is unlikely.

The same applies to the oven, it has multi elements, side, top, and back, and functions like closed door grilling, where the top and back elements work together with the fan so only need to turn food once. So it can draw some thing like 20 amps, but not for long, very quickly the thermostat starts a mark/space ratio, so the power is pulsed on/off.

So in the main a single 32 amp supply can be used for both hob and oven, however you need to read the instruction manuals to confirm this.

 

[NHW]

Not sure why the op thinks 10.0mm2 cable is rated at only 44amps.

Sorry, saw the 44a and assumed that's what it meant lol

 

[ebee]

It might be a C Y A exercise by the manufacturers/retailers but in many instances depending upon how/where the cable is actually run it will indeed carry far more than they have said.
If someone invents a very unusual way for such cable to always be safe if running 1V at 1Amp maximum then would they put that?

 

[Why Not Indeed]

Maybe that's the rating if you don't bother to un-coil it

 

[EFLImpudence]

Maybe it's a misprint and it's actually 5.5mm²

 

[ebee]

Well could be, or a 2.8mm and a 2.7mm T & Es in parallel even

Than reminds me. watch out for fake £7 notes, there`s a lot about these days. If someone asks me to change them I give the two £3 notes and a £1 note just as a precaution

 

[flameport]

assumed I would have to add up the W, and that both maximum W cannot exceed 10,500.

No.

Pretty much any combination of domestic electric cooking appliances can be connected to a 32A circuit.
That could be any of
standalone electric cooker
single oven and hob
double oven and hob
2x single ovens and hob
single oven, combi microwave and hob

6mm² is plenty for that, and 4mm² could be used in some circumstances.
10mm² is grossly oversized.

 

[JohnW2]

..... I have always wondered why we can't buy a fused connection unit which will take a 16 amp fuse, however in the UK 13 amp seems to be the limit.

It would obviously have to be something other than a BS 1362 fuse (what, I wonder?) since it clearly would not be acceptable to have 16A (or higher) fuses around which would fit into a BS 1363 plug.

So we jump in size from a unit which fits in a standard back box, to a massive consumer unit.

I wouldn't have said that. In terms of what is available, we jump in size from a unit which fits in a standard back box to a fairly small enclosure which can accommodate one MCB.

However, I do agree with you that it is perhaps surprising that MCBs that can be installed in back boxes are essentially not available (I think I've seen a few 'Asian' ones, but ....!!), since I feel sure they could be made. Depth-wise, a standard MCB will almost fit into a 47mm back box (probably would fit in a hypothetical double 55mm one), and the height wouldn't have to be reduced by all that much for it to fit into a single box - so I don't think it would be beyond the technological wit of man!

Kind Regards, John

 

[ericmark]

We can get thermal trips that are quite small which can handle 230 volt and 16 amp, one only has to look at the yellow 110 volt bricks, however they are thermal only, no magnetic part, so would not conform with all the requirements covered by a simple fuse.

The old Wylex fuse box started with re-wireable fuses, then when to cartridge and then MCB's and the 16 amp fuse used in them would clearly fit in the space that could be afforded in a double cooker outlet, so we could have a lower 16 amp protection for oven and still 32 amp to hob, but they are not made. You can get a unit same size as a MCB which takes the fuse, but DIN rail mount so no space saving, or more to the point some thing which looks in-keeping with wall mounting is a kitchen.

My late mothers house did have a mini consumer unit in the kitchen, with around 5 RCBO's, fed I think with 10 mm² SWA around the outside of the house, really house needed a re-wire, and it was a way to install a disabled kitchen without rewiring whole house, as RCD's would not have held in where main consumer unit was, before she died whole house was rewired, but the mini consumer unit remained, in the main due to safety, it was next to back door, and the kitchen isolator switches had been placed behind the hob, so to turn off hob with chip pan fire one would need to reach through the fire, was really no point having the isolator there, but where the main consumer unit was under the stairs did not have wheel chair access, in 1954 when the house was built no one thought about disabled access.

 

[ebee]

I think in the last 20 years or so there are housing estates where no one thought about disabled access either. Consumer units high up over WC so you need to stand on the WC to operate it or over the door between rooms etc. Little old lady stands on chair and someone opens door and knocks are off were not a very uncommon possibility in lots of place I`ve seen. Building Regs and common sense did not prevail in some quarters of the house building trade