Oven,Hob and Extractor Hood wiring

[AndyH-SarahG]

Hi, hopefully someone could answer this for me.

I am in the process of rewiring my kitchen. 3 x double kitchen sockets are on a 2.5mm ring circuit and I have a 6mm radial cable free which I intend to use to connect to a new electric oven which I have bought. I am also replacing a gas hob and extractor hood and was wondering what circuit it would be best to connect these to? My preference is to have all three on the 6mm cable using a terminal outlet box located at ground level behind the kickboards etc is it possible to have three appliances conntected through the same outlet box?

Thanks

 

[sm1thson]

sorry Im not going to answer your question, but pose a couple more. why get rid of a gas hob? -they are far better than electric -cheaper to run, quicker to heat up, better control over heat (or are you replacing for another gas hob one that requires an electrical connection for the ignition?).

then 3xdouble sockets -doesnt sound enough to me. maybe 3x double sockets above the worktops with more sockets below (fed via dp switches above) for washing machine, fridge etc.

 

[AndyH-SarahG]

Sorry I wasn't particularly clear, it is a new gas hob which I have replaced. The washing machine and fridge are fed by separate sockets. The six sockets above the worktops are just for appliances etc.

 

[securespark]

What rating is the oven?

 

[AndyH-SarahG]

Hi, its a 230v single oven requiring a 16A fuse. I have a 45A double pole switch in position for it. I also have a terminal outlet box for the oven connection. Is it safe to connect both the oven and the hob to the terminal outlet box? It would save me running a spur from another socket on the ring circuit.

PS - is the 45A switch ok to use or is it too powerful?

Thanks

 

[Steve]

what is the POWER RATING of the oven? It will say somewhere on it, a rating in WATTS, KILOWATTS, KW, W. Tell us this and we will advise further.

the hob needs to be fused down to 3 amps.

the extractor needs to be fused down to 3 amps.

the oven (probably) needs to be fused down to 13 amps (16 amps is a euro thing, our 'lectric is different)

how do you intend to power and protect all 3 from the same supply?

 

[AndyH-SarahG]

Hi there. The oven power is 3.7kw. The power for the extractor hood will now come from a separate socket therefore protected by the fuse in the plug. I was hoping to have the hob wired to the terminal outlet box along with the oven but it looks like I may have to add a plug for this and protect it in this way. With regards to the oven, I was intending to use the 45A cooker control switch already in place but if I understand you right, this will probably have to be downgraded to a 13A control switch. Would this mean that the 6mm cable would also have to be replaced with a 2.5mm cable? Just trying to keep the job as straight forward as possible. Thanks very much for your help.

 

[Steve]

ok, ignore my rant about 13 amps and anti-europism lol.

What size MCB is feeding your cooker control unit? Fit a 16 amp one. And fit a single unswitched socket next to the cooker outlet plate, for the hob. Sorted.

You can keep the 6mm cable and 45 amp switch. the circuit is over-rated, but this is never a bad thing so long as it is protected adequately (16 amp MCB)

 

[AndyH-SarahG]

Hi, it looks like a 40amp (Wylex-NSB40 MCB). I'll replace this with a 16amp.

With regards to the unswitched hob socket, as I am still to complete the circuit, I could build this into the ring as opposed to a spur. Would this be acceptable?

Thanks again.

 

[Steve]

IMO, it is better to wire this socket to the cooker outlet, since then it is isolatable from above the worktop. it would be a lot of work to fit another switch above the worktop etc. this way, the cooker switch actually does isolate ALL of the cooker. It is the way I have done mine. (well, ok, electric hob, gas oven, but same idea)

 

[RF Lighting]

You could feed it off the kitchen ring, but you would need some form of accesible isolator to switch the socket off if it is not readily accesible (behind the oven etc)

<bah too slow>

 

[AndyH-SarahG]

Ok, I like the sound of this. I gather the feed of new cable from the cooker outlet needs to be 6mm aswell?

Thanks

 

[securespark]

Strictly speaking, you should wire any extension to the cooker circuit in the same size cable (ie 6mm²). However, you are fitting a much smaller MCB. As long as cable sizes meet or exceed the MCB rating, you should be OK.If oven is 3,7kW, that equates to 16.09A at 230V....

I would up the breaker to 20A. Then, if you wish, and the socket is fed in cable suited to 20A, you could tap off the cooker circuit with a double for the hob & hood.

 

[AndyH-SarahG]

Ok, thanks very much for your help once again.

One final point, the control switch I have includes a scoket which will be used for nothing other than powering a kettle etc. On this basis do you think a 20amp MCB should still be sufficient?

 

[Steve]

One final point, the control switch I have includes a scoket which will be used for nothing other than powering a kettle etc. On this basis do you think a 20amp MCB should still be sufficient?

I'd get rid of it, to be honest, and replace it with one without a socket. however, if you are keeping it, dont up the MCB further than 20 amps, because it is still the primary protection for the oven. I wouldn't even go above 16 (since this is what the manufacturer says, and the load from the hob is intermittent, and very trivial), but i'm no sparky.