Mains electricity supply for gas oven and hob

[Chris Cowley]

My old gas cooker was a free-standing one with an AA-battery powered ignition system. The new (built in) oven and hob require a mains electrical supply for their ignition and the oven light. The installation instructions for the oven state that it must be connected via a double-pole switch and protected by a 13A fuse.

What I intend to do is replace a socket on the ring with a DP "cooker" switch and have this switching a new 13A double socket into which the oven and hob will be plugged.

I'm not sure whether I'd be better off using two 13A FCUs instead of the double-socket, but then I don't think I can have two separate FCUs from the DP-switch as one will be a spur-off-a-spur. I haven't been able to find a 2-gang FCU, which is why I'm thinking of using a standard double-socket.

Is this a reasonable way of doing this? Is there a better way?

[Chris Cowley]

For the sake of clarity, here's some ASCII art:-

______

---ring----------|45A DP|-------ring------ |______| | | | ___|___ |Sockets| |_______|

"45A DP" is the double-pole cooker switch. "Sockets" is a two-gang 13A socket into which the oven and hob would be plugged (tucked away somewhere discreet, probably inside a unit). The instructions for the oven state that a "13A socket outlet" is suitable, so I guess my question really is: is it acceptable/correct to have the (gas) hob plugged into the same switched spur as the oven?

[Owain]

Spur off a socket (or ring cable) to an FCU, use a junction box on the load side of the FCU to connect both hob and oven.

Owain

[Owain]

amended

______ ---ring----------| FCU |-------ring------ |______| | | | ___|___ |J. Box | |_______| | | | | | | | | | | | | oven---------| |---------hob

1 x FCU and JB cheaper than DP switch, double socket etc.

Owain

[Dave Plowman (News)]

No need to use a cooker switch as these are 45 amps. Or indeed to use FCUs. If it's plugged in that provides the necessary isolation for servicing, as well as the plug fuse providing protection.

[Chris Cowley]

That makes perfect sense to me and is what I was originally intending to do, but the thing that is throwing me off is the fact that the instructions for the oven state: "It is necessary that you install a double pole switch between the oven and the electricity supply (mains), with a minimum gap of 3mm between the switch contacts...".

I personally find this odd given that the only electrical power required by the oven is a single 25W light bulb, and the igniter (which is presumably no more than a couple of hundred milliamps). There isn't even so much as a fan, so a DP switch seems rather unnecessary, but there it is in black and white! I wasn't sure if this was a typical requirement or not.

I'm leaning towards having a DP-switch on the kitchen ring, with an FCU and the rest as per Owain's post, if that is regs-compliant (I wasn't sure that I'd be allowed two items on one switch) as that would satisfy the installation guide for the oven. I very much doubt the hob will be required to be on a DP switch, but it makes sense to me to have both items on the one switch if it's allowed.

[Chris Cowley]

[snip]

Many thanks for that, it makes perfect sense but see my other post about the instructions for the oven being very particular about specifying a DP switch. I don't understand why this is at all, but I will go along with it - as long as going along with it is regs-compliant.

[Owain]

An FCU will be a double pole switch and should have a 3mm contact gap - they're generally accepted as providing "isolation" anyway; I can't see the Council Part P Inspector complaining

You can have what you like on the load side of an FCU.

Owain

[David Hansen]

On Tue, 07 Mar 2006 10:27:48 +0000 someone who may be Chris Cowley wrote this:-

Fixed equipment should be connected with fixed wiring, not a plug and socket.

I assume that you have a gas oven and a gas hob. The ignition and oven light for these are most unlikely to draw more than 1A. Bearing in mind that I have not seen the kitchen, what I would do is fit a switched fused connection unit in the ring main, near the socket, fitted with a 3A fuse. From there I would run a cable to two cord outlets in a suitable place. These could be mounted on a metal or plastic box that takes two single items, or mounted separately. The plastic ones are certainly made by MK and perhaps other suppliers, most B&Qs will have the metal version.

the surface mounted plastic version.

[David Hansen]

On Tue, 07 Mar 2006 16:34:05 +0000 someone who may be Chris Cowley wrote this:-

A switched fused connection unit has such a switch built in

then need suitable cable outlets.

[Dave Plowman (News)]

If it comes with a fitted 13 amp plug?

How is a gas oven or hob more 'fitted' than a washing machine, etc?

[Chris Cowley]

I broadly agree that permanently wired outlets are be preferable, but just to add to the confusion slightly, although the oven doesn't come fitted with a 13A plug the instructions do state that a 13A socket outlet is a valid option (just before it goes on to say about the DP switch). Obviously that doesn't supercede whatever the IEE regs say on the matter though (I do have a copy of the 16th Edn, and the OSG, but they're up in the loft and I'm feeling too lazy to pick through them to form an opinion at the moment!).

[Chris Cowley]

Gotcha, thanks for your help.

[Chris Cowley]

That looks like it's exactly what I'm after, cheers. I'll get hold of one of those and use a junction box as described be Owain, with fixed cable outlets.

[David Hansen]

On Tue, 07 Mar 2006 19:44:03 +0000 (GMT) someone who may be "Dave Plowman (News)" wrote this:-

Cut it off.

A built in oven and hob are fixed equipment, because they are fixed:-) A washing machine is not fixed.

[Dave Plowman (News)]

Well, that makes sense. ;-)

Built in ones are as much as ovens.

[Lobster]

What's wrong with simply using the following arrangement, where "Sockets" is a 2G, DP double socket, fitted out of the way but accessible below the worktop?

---ring------------- ---ring------ | | | | | | | | __|_|__ |Socket | |_______|

David

[Christian McArdle]

All FCUs and most modern switched sockets have double pole switching with

3mm contact gaps. Older socket designs have single pole switching.

Christian.

[Christian McArdle]

Not quite. Most built in washing machines are just freestanding with the ability to attach a door. They don't screw to anything.

An oven would require a screwdriver to remove.

Christian.

[Chris Cowley]

Ahah! That explains everything, then. In my mind, a "double pole switch with 3mm contact gaps" meant a gert big 45A cooker switch. I haven't got around to buying a switched FCU yet, but it's good to know that a standard it will fully satisfy the installation requirements as well as the IEE regs.

It should look a bit more discreet than a 45A electric cooker switch too!