Kitchen Island Electrics

[RonnyRaygun]

Working my way through my self build extension and am almost at the point where I pour my concrete slab (above insulation).

My island is to have an induction hob and an oven. I believe that they will both need their own supply, so I plan to run two 20mm conduits under the slab, each with a sweep bend, ready for the electric cables to be installed later.

Any comments on my proposals?

The other question is where should the isolator switches go? I'm thinking they should be on a wall away from the island - any issues with that?

I will be getting an electrician in to install the electrics but I want to ensure that I have everything correctly prepared for when they arrive.

Cheers,

Craig.

 

[Taylortwocities]

First comment.
Allow for your two appliances to need 6mm cable. You wont get 6mm through 20mm conduit. Do 25mm, or use a length of 1.5mm drain pipe with sweep bends and run both cables through that.

Isolators are not an absolute necessity. If you feel tht you must have them then site them wherever is handy.
Ignore anybody who tells you an isolator must be within 2m of the appliance - its hokum.

Better to have the electrician specify the cable and runs before you pour your slab.

PS what's your plans for other electric on the island? I would want at least a couple of 13A sockets for kettle, fondue, phone charging etc. So that's one, maybe two bits of 2.5mm as well.
Maybe run in additional cables for plinth lighting.....

 

[RonnyRaygun]

Thanks for the reply. I like the drain pipe idea. What do you mean though by 1.5mm drain pipe? I'm thinking 32mm solvent weld pipe would be large enough to get all of the cables through.

If I was to use 32mm or even 40mm pipe would there be any issues with cutting a slot into the insulation to ensure I get the full concrete thickness over the top? Would that prevent heat from dissipating sufficiently?

I agree that it would make sense to have some 13 amp sockets on the island - not sure what type but as long as I've prepared for them by laying some conduit ready then I can cross that bridge when I come to it. Same with the isolators - can decide later whether or not to bother with them but at least having them on a wall 2m or more away won't be an issue.

Cheers.

 

[chivers67]

I had to run a 16mm in for an American induction hob once! We put an isolator inside the Island as it came with a thick HOFR cable. I agree with TTC, if you do run conduit / copex rod it with a draw rope before putting it in too

 

[JohnW2]

Thanks for the reply. I like the drain pipe idea. What do you mean though by 1.5mm drain pipe? I'm thinking 32mm solvent weld pipe would be large enough to get all of the cables through.

I would assume that's what TTC meant, and that his typing fingers disobeyed him! Mind you, whilst you were at it, you probably might as well use 40mm solvent weld pipe - which would give you that much more room, particularly for manipulation around bends.

Kind Regards, John

 

[JohnW2]

Ignore anybody who tells you an isolator must be within 2m of the appliance - its hokum.

Not only is it hokum, but if one wants the reassurance of a local 'emergency switch' (not 'isolator'), my personal view is that it specifically should not be too close to the appliance, since one doesn't want to have to lean over the appliance, or even get too close to it, if there are flames shooting out of it!

Kind Regards, John

 

[rsgaz]

If you do want isolators on the wall, this will help because then they can be fed from above in T&E cable, then switch over to 'singles' to be fed under the floor through the steel conduit. Singles are so much easier than trying to cram T&E through it.

Also, if you don't, then on the wall where these cables emerge from the floor, the cables won't be in a 'safe zone', so you'll have to run the steel conduit all the way up the wall and earth it, which will make pulling T&E through it impossible!! (pedants: yes, I know there are other ways of complying!)

 

[rsgaz]

Oh, I just re-read the OP. Do you mean steel conduit BTW, or plastic?

I assumed steel, because you mentioned swept bends.

 

[RonnyRaygun]

Oh, I just re-read the OP. Do you mean steel conduit BTW, or plastic?

I assumed steel, because you mentioned swept bends.

I meant plastic, (found some swept bends by googling as I haven't got the equipment to bend plastic pipe), although not an issue if I go for 40mm solvent weld pipe. Will a standard 90 degree bend be OK?

 

[rsgaz]

Will a standard 90 degree bend be OK?

If you mean this sort...

Then no. There are 'slightly more swept' versions though...

...so, maybe!

At the wall end though, you're not allowed to chisel out a 40mm chase, unless your inner leaf is 120mm thick. You can only chase out 1 third for a vertical chase. Are you battening out that wall?

3 x 25mm steel conduits is the best solution still, and solves some of the issues, but probably the most expensive.

 

[Taylortwocities]

At the wall end though, you're not allowed to chisel out a 40mm chase,

He would probably only have the pipe in the floor. No chases needed. Cables up the wall, clipped/capped to background and plastered over.

 

[JohnW2]

Then no. There are 'slightly more swept' versions though...

Indeed - or, alternatively, a couple of these, joined with a very short length of pipe (giving a total of 90° bend)...

... I've done that in the past, but whether or not it makes it easier to feed cables through, I'm not certain.

Kind Regards, John

 

[Taylortwocities]

And yes 1.5inches. Sorry. Bloomin Europeans, get me all confused with their strange ways of doing things.

 

[winston1]

It is normal to put oven and hob on one 32 amp supply. Why do you want two supplies? Indeed ovens and jobs can come as one unit called a cooker with one supply.

 

[EFLImpudence]

My island is to have an induction hob and an oven. I believe that they will both need their own supply,

No. It depends how you want it to work.
If you want a fault on one to NOT take out the other then have two.

The other question is where should the isolator switches go? I'm thinking they should be on a wall away from the island - any issues with that?

If they are classed as emergency switches then they should be obvious and readily accessible.
I would say on the other wall is pointless so may as well not bother.