Adequate combination for oven/hob/fan?

[GeneralNewsletter]

Hi. I am having a new kitchen and am replacing a gas cooker with an electric oven, hob and extractor fan. The cabling for these will run in trunking behind 5 cabinets before reaching the oven etc, so I want to check the cables are adequate before I put the cabinets in place. I plan on one 6mm t&e and one 4mm t&3. The 6mm for the hob and the 4mm for both the oven and the extractor. Given the values below, does this sound adequate? I will be getting an electrician to actually wire the appliances in and to connect the other ends to the consumer unit. Thanks.

The oven is a 3.49 KW,
The induction hob is 7.4KW,
The extractor fan is 158W.
The run from the CU to the appliances is around 5m.

 

[Murdochcat]

Ask the spark you expect to sign it off is my advice

 

[GeneralNewsletter]

Thanks for the quick reply Murdochcat. I don't actually have anyone lined up for the electrics yet as the kitchen is being done in two sections. The first 3m or so, is just cabinets, the second half, further along, is where all the appliances are. The cabinets for the first half are currently sitting in the front room. The appliances, sink, etc for the second half haven't been delivered yet hence not having anyone booked. I just want to get the right cables in the trunking so we can put the cabinets in place. Fair point though, I'll try to get the electrician booked for the appliances and when they quote, confirm the cable requirements. Cheers.

 

[ebee]

So the Electrician will be installing the cables before the cabinets cover the routes up? or has agreed to let you do that part under an adequate degree of supervision?
When I was a registered competent person I would not agree to an ordinary person installing those cables but if it was say a fellow Electrician I might allow them to do that bit under my adequate supervision.
You will need to confirm all of this with your registered electrician prior to starting the job first, otherwise you might encounter problems with sign offs.

 

[GeneralNewsletter]

Hi. No, the idea was that I would install the cables (i.e. just put them in some trucking that I have attached to the wall). Connecting to the CU at one end and wiring to the appliances at the other I was always going to ask the electrician to do. I see it makes sense to get an electrician involved early doors and I now have one booked in to come and quote for work, so when he comes I'll check if he is OK with me putting the cables in and confirm the cable sizes. Hopefully that will allow us to get the new cabinets in place and get the front room back!

 

[JohnW2]

I plan on one 6mm t&e and one 4mm t&3. The 6mm for the hob and the 4mm for both the oven and the extractor. Given the values below, does this sound adequate? I will be getting an electrician to actually wire the appliances in and to connect the other ends to the consumer unit.

As has been said, you need to discuss this with the electrician who you will be expected to 'sign off' the work'.

However, if that electrician is sensible/competent, he/she will probably (hopefully!) tell you that you don't really need two cables, and that one of just 4mm² would very probably be adequate.

Kind Regards, John

 

[GeneralNewsletter]

Hi John. Yes, as above, I now have an electrician booked in to quote and will check with him.
Thanks for your answers all. I'll post on here what the electrician says, in case anyone is interested .

 

[GeneralNewsletter]

The electrician has just been and he said 1 x 4mm (hob), 1 x 2.5mm (oven) and said they would run the extractor fan from the existing ring circuit. As his company will be signing it off, that's what I'll go with. It's odd that, as I've seen on forums before, for such a prescriptive industry, there can be differing opinions on these things. Anyway, the electrician is happy with me putting the cable in the trunking myself, which means I can do that and then get some of the cabinets into place, whilst I wait for them to come and do their bit. Thanks again for your replies.

 

[EFLImpudence]

However, if that electrician is sensible/competent, he/she will probably (hopefully!) tell you that you don't really need two cables, and that one of just 4mm² would very probably be adequate.

 

[JohnW2]

.... However, if that electrician is sensible/competent, he/she will probably (hopefully!) tell you that you don't really need two cables, and that one of just 4mm² would very probably be adequate.

Well, I was talking about a "sensible/competent" electrician, and not all necessarily qualify as that

A separate 2.5mm circuit for the oven is presumably not actually necessary.

 

[ebee]

well whether one puts all the items on one circuit or not it is unlikely to make much difference in the scheme of things in normal everyday use, I don`t think that anyone said it was wrong but more probably unnecessary.
Using two cables might make it more expensive though.

I did a rewire for a pal of mine with about twice as many of each lighting and power circuits than most would do. purely for extra resilience in case a circuit had to be down for any reason.
Of course, the whole install relies on one big fuse but other than that it gave that possible advantage.

 

[JohnW2]

well whether one puts all the items on one circuit or not it is unlikely to make much difference in the scheme of things in normal everyday use, I don`t think that anyone said it was wrong but more probably unnecessary.

As you say, I don't think anyone has suggested that it would be 'wrong'.

Using two cables might make it more expensive though.

Inevitably, I would say, since the 4mm² one alone would be adequate for both appliances - so everything spent on the 2.5 mm² cable would be 'unnecessary'.

Kind Regards, John

 

[ebee]

Almost inevitable John

 

[JohnW2]

Almost inevitable John

I suppose that's consistent with what I always say (and was taught), - namely that statements with 'extreme superlatives' are almost always wrong

However, provided only that the oven and hob are relatively close to one another, I struggle to think of how it could fail to be more expensive to buy additional 2.5 mm² cable if the 4 mm² cable (which have to be there, anyway) were adequate for both appliances.

Kind Regards, John