New double oven and hob

[Jason2011]

So I used to have a free standing oven with hob on top. It was fed from the board on a 40 amp mcb in 6 mm cable via a oven outlet plate. I have now got a separate double oven and hob. Can I take two 6 mm cables from the oven outlet plate one to each piece of equipment? Leaving the 6 mm supply and 40 amp mcb as I believe 6 mm t and e takes 40 amps. And therefore the cable us protected

Also the hob comes pre wired in some rubber flex, this is not long enough so I'm assuming it will be ok to change this to 6 mm t and e?

Thanks for any help[/code]

 

[ban-all-sheds]

So I used to have a free standing oven with hob on top. It was fed from the board on a 40 amp mcb in 6 mm cable via a oven outlet plate. I have now got a separate double oven and hob. Can I take two 6 mm cables from the oven outlet plate one to each piece of equipment?

A dual cooker outlet plate will be needed - you'll struggle to get 2 x 6mm² into one terminal.

BUT - what do the instructions for the oven say about cable size and MCB rating?

Also the hob comes pre wired in some rubber flex, this is not long enough so I'm assuming it will be ok to change this to 6 mm t and e?

Quite possibly not - the terminals may not be designed to take that type of conductor, the cable grip may not be designed to take that shape cable, and PVC T/E may have the wrong temperature rating.

If you need to replace the cable use the same sort - what it is it will be marked on the outer sleeve.

//www.diynot.com/wiki/Electrics:harmonized-wire-code

 

[Jason2011]

The instructions say 4.8kw on 32 amp fuse for oven and hob 6.2 kw on a 30 amp fuse and has a lead pre wired.

What the best way to install these, as before I have a 6 mm t and e supply from 40 amp mcb to cooker outlet with two 6 mm t and e to each appliance. Would this work if I took one to the oven and another to a jb where I could connect the pre wired hob into? And if so would this jb have to also be 40 amp rated?

 

[AndyPRK]

Get a dual outlet plate to connect the two appliances cables at the wall

 

[ericmark]

Two MCB wide boxes

are made so you could split into two 32A supplies in the kitchen but they are surface mount and don't look that good.

This problem is being discussed at the moment with another post there seems to be no easy way to split a non standard supply between oven and hob.

The standard is 32A and although my stand alone cooker could with all items switched on draw well over 32A it still is supplied with a 32A supply.

The oven is the problem with the hob should the power fail it just fails safe but with the oven if power fails only if the carcase is matched to that oven can we assume it will fail safe. Once cooling fans stop the carcase can over heat.

However power can fail without a MCB tripping so in real terms the carcase should match oven. In which case feeding both from a 32A may on the rare time cause the supply to trip but in the main there is unlikely to be a problem.

6mm² twin and earth is rated 47A clipped direct but it is rare for that installation method to be used. Normally method 100 is used somewhere in the run so in the main 6mm² thermoplastic insulated and sheathed flat cable will be rated at 34A.

If it were me I would feed both hob and oven from same cable and swap the 40A MCB for a 32A MCB and I would not expect there would be a problem.

However do wait for other replies.

 

[Taylortwocities]

The instructions say 4.8kw on 32 amp fuse for oven and hob 6.2 kw on a 30 amp fuse and has a lead pre wired.

What the best way to install these, as before I have a 6 mm t and e supply from 40 amp mcb to cooker outlet with two 6 mm t and e to each appliance. Would this work if I took one to the oven and another to a jb where I could connect the pre wired hob into? And if so would this jb have to also be 40 amp rated?

You could but the JB must be rated AT LEAST to 40amp and be capable of handling 6mm conductors.

One of these perhaps http://www.tlc-direct.co.uk/Products/AAJB60.html

or better to cable to a dual connecvtor box and separate wires to the appliances

 

[AndyPRK]

Oh rite. The hob flex isn't long enough apparently

 

[Jason2011]

Ok I think if I swap the mcb for a 32 amp then I have protected the cable as said under method 100 it's 34 amp rated. So ill change this and also feed the appliances from the same outlet. So the final thing is the flex on the hob it looks like it's rubber and heat resistant so does that mean it would not be wise to use t n e or is this slandered practice to use this for hobs?

 

[Jason2011]

Next question is I have wylex type 1 mcbs is there an equivalent that will fit the consumer unit now?

 

[ericmark]

Type 1 to 4 was replaced with B to D and the closest to type 1 is type B.

 

[ban-all-sheds]

Get a dual outlet plate to connect the two appliances cables at the wall

A dual cooker outlet plate will be needed - you'll struggle to get 2 x 6mm² into one terminal.

So the final thing is the flex on the hob it looks like it's rubber and heat resistant so does that mean it would not be wise to use t n e or is this slandered practice to use this for hobs?

Quite possibly not - the terminals may not be designed to take that type of conductor, the cable grip may not be designed to take that shape cable, and PVC T/E may have the wrong temperature rating.

If you need to replace the cable use the same sort

 

[AndyPRK]

There is a type1 MCB on eBay for £6. Other eBay listings are much more expensive.

But if it were me I don't think I would bother changing it. Presumably the original electrican selected it correctly for the cable run.

It will allow you more power available.
It does disagree with the MI but they didn't know you would be connecting 2 appliances.

 

[JohnW2]

6mm² twin and earth is rated 47A clipped direct but it is rare for that installation method to be used. Normally method 100 is used somewhere in the run so ...

Is that really true? Cookers/ovens are usually on the ground floor and I would not have thought that it is common to have insulation above ground floor ceilings, certainly in older buildings (do regs perhaps now require that for new builds?). Also, for houses 'beyond a certain age' you will rarely find insulation in any of the walls, either, in which case even methods 102/103 are not likely to apply.

Whatever, applying the usual guideline diversity calculation for cooking appliances, even with method 100, 6mm² cable would be good for about 90A (over 20kW) of cooking appliance 'maximum load', so I don't see that there would be any problem. Even method 103 ('the worst', I think) would be no problem.

Kind Regards, John