Wiring a single oven to a 13a plug?

jscott08

I've recently had the electrics redone in my flat, now fitting my kitchen. I've had the bottom put in:



It's on its own circuit to the breaker. I've wired the grey wire directly in to hob, I assume i therefore should be plugging in the oven. I checked the spec of the oven, it's 0.79kw (single oven). Would i be fine to wire this in to a 13a plug? If so, which cable should I use? The back says 'minimum cable H05VV-F4 mm^2' - I have some H05VV-F but its 1.5mm, not sure if this is ok

phill99

If you aren't sure, you shouldn't be doing it. Get a professional in.

tacpot12

I think you have misread the spec of the oven. 0.79kw is way too low to be correct, and this is clear from the manufacturers specification of the cable. 4mm^2 would only be specified if the load was more than about 25Amps which means the oven is at least 5.75kw. You need to use the correct cable for the oven: H05VV-F cable with 4mm^2 conductors.

This is a quite a large cable and should, ideally, be terminated onto the cooker control unit shown in the photo, but if the electrician has run a grey cable to the oven location you could connect the H05VV-F cable to the grey cable. The connector shown in the photograph is NOT suitable for this as it has no provision to connect the earth to the oven. If I was being generous, I would say that the electrician has supplied this connector to protect you from accidental electrocution and no other purpose. I wonder if they told you this, or if they were expecting you to contact them to make the final connections and you are trying to save money?

If you have connected the hob to the grey wire, then you have a problem because you need wire to be connected to the Oven.

The Hob can be plugged into the 13A socket, if it needs no more that 13A. If it is an electric hob there is a good chance that it needs a lot more than that. If so, you need ANOTHER cooker circuit running from the Consumer Unit.

It is traditional to observe that you would be better to pay the electrician to make the final connections of the hob and oven as you appear to be out of your depth with this, and this could cost you your life.

jscott08

tacpot12 wrote: »

I think you have misread the spec of the oven. 0.79kw is way too low to be correct, and this is clear from the manufacturers specification of the cable. 4mm^2 would only be specified if the load was more than about 25Amps which means the oven is at least 5.75kw. You need to use the correct cable for the oven: H05VV-F cable with 4mm^2 conductors.

This is a quite a large cable and should, ideally, be terminated onto the cooker control unit shown in the photo, but if the electrician has run a grey cable to the oven location you could connect the H05VV-F cable to the grey cable. The connector shown in the photograph is NOT suitable for this as it has no provision to connect the earth to the oven. If I was being generous, I would say that the electrician has supplied this connector to protect you from accidental electrocution and no other purpose. I wonder if they told you this, or if they were expecting you to contact them to make the final connections and you are trying to save money?

If you have connected the hob to the grey wire, then you have a problem because you need wire to be connected to the Oven.

The Hob can be plugged into the 13A socket, if it needs no more that 13A. If it is an electric hob there is a good chance that it needs a lot more than that. If so, you need ANOTHER cooker circuit running from the Consumer Unit.

It is traditional to observe that you would be better to pay the electrician to make the final connections of the hob and oven as you appear to be out of your depth with this, and this could cost you your life.

Thanks for the info, very helpful. I assumed the same with connector - that the electrician put it on to keep the wires safe as i had no kitchen so the wire was loose on the floor. I took the block off and connected it properly directly in to the hob (obviously switched off at the breaker first and tested).

As for specs, you're right, those specs are wrong - I had a look online as I couldn't find the specs on the oven, seems they differ. I've finally found the sticker (it was on the bottom), and it's 2.9kw. The hob is ceramic, 6.5kw, so definitely can't be plugged in.

I had essentially all my electrics redone with a new consumer unit. The plug and cable in the pic are the only things on the cooker circuit to the breaker. I'm now wondering, If i need to wire the oven directly as well, has the electrician just done a bad job here?

tacpot12

If the oven is 2.9kw, then it can be plugged into a 13A socket - it will draw 12.9A.

The hob will draw 28.2A giving a total draw on the cooker circuit of about 42A, if you plug the oven into the 13A socket on the cooker control unit. The circuit breaker is very likely to be rated at 32A, and so load of 42A will overload it and it will trip.

A 32A breaker might have been adequate if we apply the concept of diversity. The concept of diversity (as referred to by electricians) recognises that if the hob has four hotplates, it is highly unlikely (at least in a domestic setting) that all the hot plates will be drawing power at the same time. So the actual load is likely to be less than the theoretical maximum load.

The calculation for diversity that I would apply is 10A + (3/4 * 18.2A) + 13A which gives a design demand of 36.65A, still too much for a 32A Breaker.

Do check the breaker to see if it is really 32A, there is a chance it could be 40A, in which case, you are ok to plug the oven into the socket on the cooker control unit.

If it is not 40A, I would leave the hob connected to the cooker control unit, and find another way to supply the oven. lf the rest of the kitchen sockets are supplied by a 32A breaker on a ring circuit, having the oven on that circuit will not be too much of a problem, but if the kitchen sockets are only supplied by a 20A breaker on a radial circuit, you will have precious little capacity for anything else (7A). Even a kettle would be too much. If you have a washing machine, tumbledryer and dishwasher you are going to really struggle. So if the kitchen sockets are on a 20A radial, you are going to need the electrician to come back and redesign the supply to the kitchen. Depending on access and the distances involved, it might be easier to run a new circuit in for the oven, or to upgrade the cooker circuit to supply 40A. I'm inclined to think that a new dedicated circuit for the over is the best option here.

You can't really say the electrician did a bad job if you didn't tell them the make and models of the appliances you were going to fit. If you have done so they could have looked up the demands, and produced a design that allowed everything to be fitted.

brightontraveller

tacpot12 wrote: »

If the oven is 2.9kw, then it can be plugged into a 13A socket - it will draw 12.9A.

The hob will draw 28.2A giving a total draw on the cooker circuit of about 42A, if you plug the oven into the 13A socket on the cooker control unit. The circuit breaker is very likely to be rated at 32A, and so load of 42A will overload it and it will trip.

A 32A breaker might have been adequate if we apply the concept of diversity. The concept of diversity (as referred to by electricians) recognises that if the hob has four hotplates, it is highly unlikely (at least in a domestic setting) that all the hot plates will be drawing power at the same time. So the actual load is likely to be less than the theoretical maximum load.

The calculation for diversity that I would apply is 10A + (3/4 * 18.2A) + 13A which gives a design demand of 36.65A, still too much for a 32A Breaker.

Do check the breaker to see if it is really 32A, there is a chance it could be 40A, in which case, you are ok to plug the oven into the socket on the cooker control unit.

If it is not 40A, I would leave the hob connected to the cooker control unit, and find another way to supply the oven. lf the rest of the kitchen sockets are supplied by a 32A breaker on a ring circuit, having the oven on that circuit will not be too much of a problem, but if the kitchen sockets are only supplied by a 20A breaker on a radial circuit, you will have precious little capacity for anything else (7A). Even a kettle would be too much. If you have a washing machine, tumbledryer and dishwasher you are going to really struggle. So if the kitchen sockets are on a 20A radial, you are going to need the electrician to come back and redesign the supply to the kitchen. Depending on access and the distances involved, it might be easier to run a new circuit in for the oven, or to upgrade the cooker circuit to supply 40A. I'm inclined to think that a new dedicated circuit for the over is the best option here.

You can't really say the electrician did a bad job if you didn't tell them the make and models of the appliances you were going to fit. If you have done so they could have looked up the demands, and produced a design that allowed everything to be fitted.

[FONT=&quot]Are you serious [FONT=&quot]looking at the socket/outlet install I'd say get the house checked by a real electrician thats a complete bodge [/FONT]
[/FONT]

Ectophile

In the real world, if you took a freestanding cooker, with an oven and hob, and wired it into a 32A circuit, then no-one would bat an eyelid. It's what people have been doing for decades, and the breaker never seems to trip.


Separate the oven and hob, though, and people just add up the maximum rating of both, and decide that it can't possibly work on a 32A breaker. But actually it's not really any different.



That's especially the case since if you overload a 32A breaker at 42A, it might just trip after 4 or 5 minutes at that full load. Or it might not - it's not actually required to trip ever at that level of overload.

Owain_Moneysaver

The cooker control switch should have been fitted above the worktop with a cable dropping down to a double cooker cable outlet which has cord grips and connections for 2 cables to hob and oven eg

https://www.tlc-direct.co.uk/Products/AA45DCOP.html

Back in 16th Edition days we used 10 A plus 30% of the remainder of the total connected load, plus 5 A if the control unit includes a socket outlet (for a kettle).

The electrician (or you) should have plastered that box in properly too. And there's no g/y sleeving on the earth.

Owain_Moneysaver

brightontraveller wrote: »

[FONT=&quot]Are you serious [FONT=&quot]looking at the socket/outlet install I'd say get the house checked by a real electrician thats a complete bodge [/FONT]
[/FONT]

Plumbing's a bit rough too. No clips on the waste, and unfastened pipe clip on one of the coppers.

Carrot007

Owain_Moneysaver wrote: »

The cooker control switch should have been fitted above the worktop

I was thinking that! What use does a switch that looks like it is going to be inaccessible do!


Might be as useful as the one in the kitchen in the house I moved into. The switch did nothing as the feed went to the cooker first and then to the switch just to power the socket! To top it all off the oven would not turn off so you had to turn off at the consumer unit! The kitchen was quickly replaced.

jscott08

tacpot12 wrote: »

If the oven is 2.9kw, then it can be plugged into a 13A socket - it will draw 12.9A.

The hob will draw 28.2A giving a total draw on the cooker circuit of about 42A, if you plug the oven into the 13A socket on the cooker control unit. The circuit breaker is very likely to be rated at 32A, and so load of 42A will overload it and it will trip.

A 32A breaker might have been adequate if we apply the concept of diversity. The concept of diversity (as referred to by electricians) recognises that if the hob has four hotplates, it is highly unlikely (at least in a domestic setting) that all the hot plates will be drawing power at the same time. So the actual load is likely to be less than the theoretical maximum load.

The calculation for diversity that I would apply is 10A + (3/4 * 18.2A) + 13A which gives a design demand of 36.65A, still too much for a 32A Breaker.

Do check the breaker to see if it is really 32A, there is a chance it could be 40A, in which case, you are ok to plug the oven into the socket on the cooker control unit.

If it is not 40A, I would leave the hob connected to the cooker control unit, and find another way to supply the oven. lf the rest of the kitchen sockets are supplied by a 32A breaker on a ring circuit, having the oven on that circuit will not be too much of a problem, but if the kitchen sockets are only supplied by a 20A breaker on a radial circuit, you will have precious little capacity for anything else (7A). Even a kettle would be too much. If you have a washing machine, tumbledryer and dishwasher you are going to really struggle. So if the kitchen sockets are on a 20A radial, you are going to need the electrician to come back and redesign the supply to the kitchen. Depending on access and the distances involved, it might be easier to run a new circuit in for the oven, or to upgrade the cooker circuit to supply 40A. I'm inclined to think that a new dedicated circuit for the over is the best option here.

You can't really say the electrician did a bad job if you didn't tell them the make and models of the appliances you were going to fit. If you have done so they could have looked up the demands, and produced a design that allowed everything to be fitted.

Thanks for the info, makes a lot more sense now. I've just checked and the fuse at the breaker is 40A, although thinking about it I can't see it being a good idea trying to wire 4mm flex in to a standard plug if that's what the oven calls for.

As for the electrician knowing the make and model, they were in the kitchen before he did the work! so not only did he have the make and model, it would have taken him about 20 seconds to know the exact spec. Safe to say I won't be using him again

Owain_Moneysaver wrote: »

The cooker control switch should have been fitted above the worktop with a cable dropping down to a double cooker cable outlet which has cord grips and connections for 2 cables to hob and oven eg

https://www.tlc-direct.co.uk/Products/AA45DCOP.html

Back in 16th Edition days we used 10 A plus 30% of the remainder of the total connected load, plus 5 A if the control unit includes a socket outlet (for a kettle).

The electrician (or you) should have plastered that box in properly too. And there's no g/y sleeving on the earth.

Given I haven't put my counters in yet, should I have this changed by an electrician to the dual plate chase further up the wall? I don't want to put the counters in and tile only for this to create more problems in the future. As for the wall, agreed he definitely did not chase the box in very well. I wasn't overly bothered about it given it will be hidden but I will plaster it regardless


Given all these responses now i'm not sure what to do - should I make do with how it is or have the whole thing redone? Now would be the time, before the rest of the kitchen goes in (may also be worth noting that the fuse box is only about 2 meters from where the box is in the kitchen which probably makes things easier)