Wiring a Cooker point

[Grahamd]

I am doing some rewiring of a kitchen and need a new cooker socket. Will be fitting a built-in cooker but not sure which make or model yet. What amp cooker switch do I install (30 or 45 amp) and can you tell me what size of cable to lay from the MCB to the switch?

Many thanks.

 

[breezer]

depends what rating it is, but you could run in a 6mm cable

 

[securespark]

A six mm cable would cover you.

It could be a single oven which is limited to 3120W and could utilise a socket or FCU (fused conn unit)

Or it could be a double oven & hob in which case you can apply diversity to calculate the current use.

As follows:

10 Amps plus 30% of the full load of the appliance in excess of 10A + 5A if the cooker supply unit has a socket outlet incorporated.

SO:

If your cooker has a total rating of 12500W (52.08A), your calcs look like this:

10A +

30% of 42.08A = 12.63A

+ 5A if you have a socket incorporated. (Lets assume you do)

which equals 27.63Amps

These figures have been plucked out of thin air just as an example.

 

[ban-all-sheds]

And 27.63A looks like you could go with a 30A switch and 4mm cable, but don't be tempted to sail so close to the wind - go with 6mm etc.

4mm is typically OK for just an oven (single or double), if you've got a gas hob, but not for an entire electric cooker.

 

[Grahamd]

From what you're saying then, 6mm cable and a 30a Switch+socket will be adequate.

Cheers Guys.

 

[ban-all-sheds]

45A.

Anyway - I'm not sure you can get 30A cooker units?

 

[another_sparky]

Just a thought here,

Seeing as you havent yet bought your cooker, you might want to expand your options on the cooker choice of model.


( Some cookers work from a simple plug-in, - others require 6mm connecting to terminals at the rear of the housing.)

Seeing as your kitchen will be remodelled, you might consider running a length of 6 mm from the cooker switch to a 'cooker connection unit'

Normally sited out of view - and you connect the two 6mm 's (from the cooker and the switchplate)into here

This will give you flexibility on choice of model of cooker.

 

[totty]

( Some cookers work from a simple plug-in, - others require 6mm connecting to terminals at the rear of the housing.)
.

I wish I'd checked this forum before wiring mine, unfortunatly I took the advice of several other people who calimed all ovens only required "a simple plug in" and now I've tiled over the floor. I'm now frantically looking for a manual for the one I was going to buy with fingers crossed hoping its less than 24A (I think thats what 2.5 can take isnt it ?).
The range of freestanding dual fuel cookers with separate grill and oven is small enough without narrowing it down with electrical requirements

 

[breezer]

its usually the hob that draws the most current.

_______________________________________________

useless tip # 49

if you have a halogen hob, do not make jam

the reason is the "glass" is not glass its quartz, when it gets hot sugar will literally eat through the quartz, trust me (it also says in the small print to keep sugar away from the surface when hot)

 

[totty]

I've just found the manual it states "Electrical connection :- 230 - 240 V 50 Hz Mains connected at rear centre of appliance using at least
6mm2 multi core PVC insulated cable."

other info:
Loading info : Electric ovens
Voltage: 230 - 240 Volts AC 50Hz
Top Oven: 1.6 kW - 1.7 kW
Grill: 2.5 kW - 2.7 kW
Main Ovens
Fan Element: 2.3 kW - 2.5 kW
Fan Motor: 0.03 kW
Oven Light: 0.025 kW
Wattage: 4.8 - 5.2 kW

Can someone help me with the calcs just to be sure that 6mm2 is required please before I do anything drastic.

Also anyone got any tips for getting the cable accross a room under floorboards + ply + tiles ?
I can cope with messing up the nice new plaster since its going to be tiled over anyway but not the floor.

 

[ban-all-sheds]

5.2kW = 22A, which might be a bit close to the edge for 2.5mm, so you're into new cable time. 4mm would do, but you might as well put in 6mm in case the next owner wants an electric hob. Apparently some people do, I'm told.

If it needs to get from one side of the room to the other and it can't go under the floor then the only option I can think of is up the wall, inside the ceiling and down the wall.....

But if your kitchen floor is boarded, what's underneath? which way do the joists run? Coud you use the old cable to pull a new one through?

 

[totty]

thanks ban-all-sheds

I'd be tempted to run the 22A on the 2.5 I know its a bit close to 24A but it is only the width of a small kitchen, would that be ok ? but the MCB would then be a problem I've never seen a 22,23 or 24 so it looks like I need to replace the cable

electic hobs are cr*p compared to gas (or at least all the ones I've used are) but as you say I might as well use 6mm while I'm on.
Unfortunatly I cant easily go over the top its a flat roof so no access from above, looks like the floor or a different cooker might be my only choices.
The joists go the right way, underneath is mostly rough concrete and rubble, around a foot below. Any advice on how to join the cables to pull the new one through ? duck tape maybe ?

Thanks

Allan

 

[ban-all-sheds]

Solder them together?

The problem you'll have is that 6mm doesn't bend as readily as 2.5. Can you get at the floor void from the outside? I'm thinking that if you removed a brick and could get an arm in that might make pulling a new cable much easier

 

[totty]

I never thought of that, might combine the solder and duck tape.
I'm not sure, I'll have to do some measuring.
As an alternative to 6 could 2x 2.5 be used ? It'd be much more flexible, or there might be a good case for using 4 is there much difference in the flexability of 4 and 6 ? I've only ever worked with 2.5

 

[ban-all-sheds]

I'm sure that multiple parallel cables are not allowed - I've never seen it as a suggested solution.

As for bending - they get harder to bend as they get bigger, so 4 is noticeably tougher than 2.5, 6 is harder still, and 10mm is a right pain - very hard to bend by hand.

But unfortunately difficulty of installation doesn't negate the requirement to use the appropriately sized cable for the job