Electricity supply problem

[Yorkshire Lass]

Does anyone know much about UK electricity supply? I'm currently having a new kitchen fitted but have hit a problem. The old kitchen had a big gas range cooker but in the new kitchen which is being moved to the other side of the room I've planned to have a double oven and electric hob. The electrician who came to put the wiring in for this has told us that because we have 2 electric showers this is going to overload our current supply. The advisor from the company who are supplying (but not fitting) the kitchen has told me all I need is a new fuse board but the electrician is suggesting I need to have the power supply upgraded (3 phase meter anyone?) - this would be hugely expensive by the look of it. Help - has anyone had this kind of issue themselves? Seems amazing to me that 2 electric showers, a double electric oven and hob are too much for one house's power supply.

[greenbarn]

This is just by way of a guide only, not definitive information, but might give you an idea of what the supplier and electrician are talking about - no more than that; you'll have to go with the electrician's advice, and maybe get a second opinion. I'm not qualified to advise; I simply understand enough to know that I don't know the answer!

The oven and hob combined are likely to be rated at about 10kWatts.
Each electric shower could be rated anywhere from say 5 to 9 kWatts - call it 15kWatts for the two.
So if everything was working on full power at the same time (unlikely) that would be 25kW, or about 100 Amps current. Then you switch on the kettle, the tumble dryer etc etc, all of which also draw highish current. To complicate things, when the calculations are done electricians use a factor called diversity which is a way of averaging usage - ie you probably don't have everything on full power at the same time.

The feed to your main fuse box (consumer unit nowadays) will have a dirty great fuse in it that belongs to the electricity board, which only they are supposed to replace and will be in a box with a wire and lead seal. If that fuse is "only" 100Amps, which is quite possible, you're close to blowing it. It may not be a problem to have it uprated if the supply from the street is up to it (probably is). I can't imagine you need 3 phase, and I doubt you'd get 3 phase if you went on your knees and begged for it.

Next, your consumer unit (fuse box) should have a breaker (fuse if it's ancient) for each of the showers. There'll be thick cable (the conductors will be 6 square mm in diameter) running directly from each breaker to each shower unit, with nothing else fed from the circuit. The cooker will need its own similarly rated breaker, with a dedicated cable running from it directly to the cooker point.

So you'll almost certainly need work on the consumer unit to add an additional breaker for the cooker and run the cable to the cooker point; that's the minimum, it may be all.

If the electrician says you "need to have the supply upgraded" you need to ask him what he means, and what his calculations are to justify this (and try asking him to explain diversity). If he flounders and flannels, ask another (qualified) electrician the same question.
However, if he really does know what he's doing, you might just have a problem. I struggle to believe that, but my understanding is limited.

Good luck.

[Yorkshire Lass]

Thanks GB - yes, I do see the problem (though it had never crossed my mind before and several experienced kitchen fitters/kitchen companies who came to quote never mentioned this as an issue before either!). We're going to ditch the electric hob for a gas hob but reluctant to go for a gas double oven unless we absolutely have to. In the mean time have begun approaching the electricity meter people about getting our power upgraded and what the costs of that would be - of course you have to fill in a form and they reply in 10-15 working days! Anyway, should I need to change a kitchen in the future this is something I'm going to be well aware of....

[French Cricket]

As GB says, IANAE and do not rely on me blah blah etc etc .... but some 10 years ago in the UK we too upgraded our kitchen. As part of the refit we installed an electric double oven range cooker, and the electrician contracted by the kitchen fitting company had kittens. We and the owner of the kitchen fitting company had already checked everything out with Rangemaster to make sure there were no problems with supply, and there weren't - the oven was designed to run from normal 2.5mm cable and actually although it was twice the size technology had moved on so that it used no more power than the ordinary domestic-type cooker that it replaced.

To cut a long and very frustrating story short the kitchen fitting company ended up ditching their electrician (who was actually so neurotic that he had to wear a nappy to change a light fitting ) in favour of our regular guy, who saw no problems at all. So it was fitted as originally planned, and all was well.

We had no gas so everything was electric, on a normal domestic supply: the cooking range, four storage heaters, two electric showers, various other electric radiators, two immersion heaters, four fridges, two freezers and all the other paraphernalia. We had 2 guest suites and our tiny restaurant; the people who'd had the house before us ran an artisan bakery and tea room. No power trips. (Except the electrician's ).

So if you really want to hang on to your electric ovens (and I'd always choose a gas hob but an electric oven), YL, don't give up but get some second (third, fourth ...) opinions!

[greenbarn]

Dropping the electric hob in favour of gas may be enough to keep within the capacity of your existing supply - electric hobs pull a lot of current; you'll still need an additional breaker in the consumer unit, and the wiring work for the oven though.
Just a thought - in our house we have a modern AGA that only requires a 13Amp supply - ie it's connected in to the normal ring main, a relatively easy electrical job. Complete change of kitchen design and budget coming on..........?

[greenbarn]

(who was actually so neurotic that he had to wear a nappy to change a light fitting )

Racial Stereotype joke alert:

Q: What's black and charred and dangles from a light fitting?
A: An Irish Electrician.

don't give up but get some second (third, fourth ...) opinions!

Definitely. There seem to be some electricians out there who can get blue and brown the right way round when armed with a picture, and little else. You might need to find a contractor who's used to doing full installations (with all the calculations that can involve), including dealing with the Leccy Board, rather than someone whose normal role is adding an extra socket.