ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Connecting 110V oven to UK power supply

If it were me, I really wouldn't be bothered converting that oven. It sounds far too complicated.

Using a transformer with a cooking appliance is also not a great option as the loads are way too big. It will end up with a really messy setup.

You also run into issues with wiring regulations, at least you would here anyway.

There are potentially complications such as providing overcurrent protection on the 110V side. You would need a multi-poll 110V MCB that complies with UK standards.

There's no big deal in bringing small appliances / electronics across the atlantic either direction, but when you get up to things like cooking appliances, washing machines, dishwashers, vacuums etc it really stops being worthwhile unless someone's got some major sentimental attachment to the device!

Thanks for all your responses. I guess the "attachment" the customer has developed is due to the fact that he has paid less than 1/2 the UK price. Looking around the house, I noticed other items from the US, powered by transformers, all of which he has managed himself so far.

Looking over the web over the weekend, I have found quite a few UK sites offering transformers to US residents and US armed forces personnel who might require 110V power in the UK, from 50VA to 8KVA, so this kind of requirment can't be that rare - here is the link in case anyone is interested:

http://www.airlinktransformers.com/american-transformers.asp

I'll be calling them next week - it will be ineteresting to know if they can supply the right one.

Just bear in mind, you don't need a transformer for the 240 parts of the load and that is almost all of it. You only need 120v for the light and clock ... if you don't rewire the light.

Is it really a good idea to modify factory wiring? I aways look at altering the wiring of a appliance as a bad thing,+ the liabilty....

You may have a hard time separating the 120v ckt from the 240v. Most of these ovens use electronic switching and the control board may operate the element but it itself may be 120v both sharing common hot.

Before I say this, let me state that I have NO IDEA what is legal over in the UK - I've never been there. Here's an answer that'll work from the "electrical theory" standpoint. Figuring out whether or not it's code-compliant over on the other side of the pond is up to you.

Black and Red to the oven are hot, and the oven expects 240V across them. Wire them to your 230V mains supply.

white is supposed to be 120V from each hot, ie, it's a center-tap from the expected 240V source. As others have said, it only likely powers the light/clock, maybe a fan or two if it's some really fancy oven. Either way it'll be a (relatively) small load. Grab yourself a 240V-to-120V transformer whose rating matches the 120V part of the load, wire its primary to your mains supply (through an appropriate fuse or circuit breaker) and the secondary side from one hot to the white wire, providing the 120V.

As you noted, ground the bare wire.

As Westuplace pointed out, it's never that easy when electronics are also used to run stats etc.. With the added cost of a proper transformer creating a near enough US supply of 120-0-120, plus the sparks time in wiring it, plus freight charges, plus the warranty nightmares, plus UK Customs taxes on US imports, [ boy, are they going to wake up with a start when a massive box trundles past- while my little nozzle parcels tiptoe by unseen! ], the savings are being eaten away - and they could have got a properly engineered UK version with no problems. Sounds insane to me.

We used to have a similar situation in the US with automobiles that were bought in Europe and shipped to the US.

These so-called "grey market" cars were almost always a lot cheaper, even with the added cost of shipping the entire car across the pond. The REAL costs came when the new owners found that they had to have them retrofit to meet the US emission and safety standards. When the dust finally cleared the supposed savings had completely evaporated (and then some).

If you end up with a big transformer you have to take into account the losses in magnetizing current of the TX core, which is energized 24/7.

Even at say 50 Watts for an 6 kVA TX it adds up to a quit bit of extra power usage.

1.2 kWh day
438 kWh year

That is for the TX only !

Rod, it's easy to lose sight of how small loads tot up over 24/365. I have heat-exchanged fan ventilation,[we rarely opened a window], motor c.100w. We moved into the high-tech end of this longhouse in Nov '08, expecting a big drop in poco bills. We had spent a fortune on low-energy lights, had changed from a halogen hob to propane and I'd fitted breaker signal circuits to auto run the washing m/c and dishwasher on cheap rate at night. The bills for the first year were up!

It was that little fan motor. Do the math. 100w = 2.4kwh per day. 876kwh per year @ €0.15/average = €131 per year, wiping out all our other little economies and then some.

Now we only ventilate mechanically in the winter or when the a/c is running. Other times we use the windows!!