Repositioning oven cable outlet and isolator?

[Michael Kilpatrick]

I'm preparing various channels in the wall ready for the new kitchen wiring and some plastering. The new kitchen will be installed pretty soon.

We have an oven and a combi microwave/oven above it in a single tower and this will be replicated in the new kitchen but moved about 15cm to the right. Immediately to the left will be 300m wide base drawer unit and to the left of that an 800mm base unit with the gas hob.

The existing oven cable outlet is right where the join between the 800mm and 300mm units will be, so that seems rather undesirable. The microwave is connected via a surface mounted standard 13A socket taken from a ring main, and also hidden nearby.

I've also got to make good the wall around the isolator switch - it's a mess where the tiles used to be and it needs a new back-box for a new MK isolator. The circuit is on a 40A RCBO.

The questions are:

Is it always sensible (or a requirement) that the oven cable outlet is behind a base unit to one side of an oven tower or can I chase channels for new 6mm2 cables in the wall such that it can be behind the tower unit itself?

If I can do that, should I position it low down, behind the bottom drawer of the tower? I'm assuming directly behind the oven is a bad idea as the clearance is only 30mm or so. Or up behind the microwave where the clearance behind is 80mm?

Is there any reason why I shouldn't put the microwave on the same circuit from the isolator with a socket also behind the tower unit?

Michael

[John Rumm]

The outlet can be anywhere you like within reason. The isolator however needs to be accessible without needing to get behind an appliance, but preferably within 2m of the appliance it isolates. Isolators don't necessarily have to be on show - they could be for example in an adjacent cupboard.

Which will make it easier to wire?

probably not, but it depends on the total load. Check the maximum load of the oven and microwave (and you can apply diversity to the oven load), and check it is less than your circuit design current.

[Michael Kilpatrick]

The isolator is between the hob and oven tower. I am moving the isolator

10cm to the right to move it further away from the hob and closer to the side of tower as I'm sure it's a bit too close to the hob at the moment. Not directly over it, but close.

The original cabling from the consumer unit to the isolator is massive. Maybe 10mm2? It's certainly more than 6mm2 and it's extremely difficult to manipulate. I notice that whoever wired the original isolator cut off two of the strands of the cable so that it would fit in the connectors of the old isolator, it's that thick.

The cut-out for the isolator is a complete mess. It was moved 10cm to the left at some point in history and so I have an absolutely massive hole to render around the back box once I've positioned it properly.

The front of the old back box wasn't at all parallel to the wall face either. What a dog's dinner. More chiselling for me.

I think I'll run with that answer, thanks.

Well, it's a 2.2kW oven and the main cable is blumin' enormous and on a

40A RCBO, so I think I would find it extremely difficult to do anything even remotely out of spec there!

Michael

[Tricky Dicky]

Check the manual for the oven, the manufacturers often indicate the safe place to put the outlet. When I installed our kitchen recently I placed the outlet parallel with the isolator as there was no problems with the original tower however the new tower went in a different place and unfortunately the wall was badly out of plumb. By he time I scribed the unit to the wall the back of the oven was catching the outlet, when I moved into the position suggested by Bosch no problems.

As for siting isolators near hobs, I found out recently that any isolator or socket or switch needed to be at least 100mm from the edge of the hob. I seem to recall for gas hobs it used to be 300mm away from the centre of the nearest burner but it seems to have changed now.

Richard

[Michael Kilpatrick]

Indeed. It appeas to be 100mm from what I read online. The new position will exceeed the 100mm (from the edge of the glass base plate of the hob) by a tiny bit. The old position of the isolator actually overlaps horizontally with the glass base plate of the gas hob. Bit yukky.

Michael

[Brian Gaff (Sofa]

I'd also worry about the insulation of the oven as heat rises. I'm sure these are better nowadays, but the last thing you want is a melted or cooked isolator or socket!

Brian

[Michael Kilpatrick]

Eventually I found installation manuals online for different versions of the same model of oven each of which said that the connection point can only be behind the oven if it's within a certain small area indicated by a diagram. Otherwise, it must be outside that oven's footprint. There was absolutely nothing about not having it directly above the oven on the wall behind it, or below it (so still within the space of the tower housing).

Now, that must mean that if the connection point is above it, the cable, trailing behind the oven and from the bottom of the oven, would necessarily be lying vertically against the wall and behind the oven. Yet there are no instructions to say that is bad because of heat from the oven affecting the cable.

It's slightly dissastisfying when an installation manual doesn't explicitly say something like that, either way.

Michael

[Tricky Dicky]

I suppose it depends on the design of the tower. The one I fitted like all the other base and tall units had a service gap at the back so the cables tend to fall into that area. Our tower has two standard ovens, the bottom cable falls into the service gap behind the lower cupboard, however the upper oven cable falls into the service gap behind the lower oven. Although neither installation instructions specify the cables as heat proof but neither are there any dire warnings that the cables should be directed away from certain parts of the ovens.

Richard

[ARW]

Presumably it is using heat resistant flex and should not be a problem.

[Michael Kilpatrick]

I assume it is, and that when Magnet fitted the old kitchen in 2001 everything was as it should be.

I will inspect the flex carefully before I proceed. This work on the position of the outlet will be towards the end of the kitchen assembl, thankfully, so not desperately urgent.

Today I tried plastering for the first time ever. Hmmm. Not exactly brilliant....

The reason I'm doing plastering and *all* of the assembly of the kitchen myself is that my handyman, a friend of over 20 years, was diagnosed with bladder cancer just last week and has immediately stopped everything for treatment. Very worrying, as it's quite aggressive.

He was due to be fitting the kitchen although I would have been doing the majority of the electrics myself either way.

Michael