There's a light switch from the UK that I'd like to use in our US home. We would be using it as a light switch, its intended purpose, not to switch on anything that would draw more current than any lights would.
If the UK's power is 230V 50Hz, is it possible and safe to wire it in to our 120V 60Hz power? Using the British switch instead of a standard North American 3-gang toggle bank would work better for what we're doing. Plus it looks kinda snazzy.
You probably could do it, but since most US lighting circuits are 15 amp, and that switch is rated at 10 amp, you should downgrade the circuit breaker for that lighting circuit down to 10 amp.
The other concern is that the switch may not fit into a standard American style junction box. You might want to measure yours and then convert the British specs from metric to inch and adjust accordingly. Switching out your junction box for a British spec "back box" probably would involve some wall tear down and replastering/painting. I'd probably get to a hardware store and get a three gang American style wall switch instead...
Then the money you save can go towards a trip to London.
What kind of bulbs are you running on it? If you are running lighting only, then you should be fine.
Here's a basis for comparison
300 watts = 2.5 amps
As for the measurement, american boxes are 1.5" deep.
1.5 inch =33.1 mm
However I agree, it might be better to go ahead and get a UK box to mount it.
I sometimes eat lunch with the senior citizens, there's an experienced, retired electrician that's usually there, I can ask him tommorow to make sure also. But, yeah, you should be fine.
I think your biggest issue is going to be the mounting box. And if you want to do this up to code, remember that the number of conductors allowed in a given box is predicated on its volume.
The point about current rating will also come into play; if the contacts are only good for 10A and you have a single feed for all three loads, remember the total available current for all three can't exceed 10. Also, 10 amp breakers aren't exactly common and may not be available at all in your panel style.
You could always toss a satin chrome plate on a Broan/Leviton US style...
Maybe it's better to think in terms of watts not amps, comparing a European circuit that runs at a nominal 240 volts to a North American circuit that runs at 120 volts cannot be done without accounting for the voltage differences. If the switch is rated for 10 amps at 240v then it can handle 2400 watts, same as an American circuit with a 20 amp breaker. Just to be safe I'd keep it on a 15 amp circuit. There are some oddball breakers out there, such as a 30 amp 120v one, but if anyone does make a 10 amp 120v breaker it's likely to be very special order and only available for panels made by certain manufacturers.
Overall I think Cadman has the best idea to just use a nice quality American switch, particularly because it fits an American box. Remember that the codes are very specific about not only how many wires may be in a box but also how the wires exit the box and are fixed to the box, for instance different methods are used for Romex versus conduit.
Sent a message to the seller through Ebay. This was the response.
(basically, it won't work)
Dear artcurus3,
Thanks for the email. No it will not, we do not have any US switches I'm afraid.
Anything else please let me know.
On 11/01/2015 14:59, artcurus3 wrote:
Other: artcurus3 sent a message about Varilight 3 Gang 1 & 2 Way 10A Rocker Light Switch Matt Chrome White Insert #131241846459
Would this be okay for US installations if used for lighting only? We run 120v at 60hz. Commercial plugs and switches are rated for 120v at 20 amps. Residential ratings are 15 amp at 120 volts.
There are amp ratings for 120 and 240 volts on many switches. I was always told that transformers, switches and contacts that were designed for 50 hz would be fine for 60 hz. The issue is going in the opposite direction.
Cory and Sam are also correct about the size of boxes. I recently learned that just because you can fit wires and a device in a box, doesn't make it right. I was trying to avoid chiseling brick to update kitchen receptacles Then again, I am not a big fan of the electric code book.
Signed owner of a 1930's home with knob and tube that's just fine.
ps. That doesn't mean I am testing a Combo on a household extension cord.
If you use a U.K.-spec switch with American wiring, and - God forbid - you should have an electrical fire, your insurance company will do everything in its considerable power to blame the fire on the switch, thus dodging your insurance claim.
I understand completely that this is a cool switch, that it would probably work just fine and that it probably would not actually be at fault. But somewhere down in the finest of the fine print in your policy is some kind of escape clause that lets your "good neighbor in good hands" off the hook if you use non-U.S.-code-compliant bits in your wiring, trust me.
I disagree that thinking in terms of watts instead of amps is a good idea.
Amps are amps, regardless of voltage. For example, a six volt automobile electrical system must use much thicker conductors than a 12 volt system of similar load capacity. Why? Because at twice the voltage, only half as many amps are needed. Similarly, at half the voltage, twice as many amps are needed for the same load.
A 10 amp circuit at 240 volts can carry 2,400 watts (resistive load). A 10 amp circuit at 120 volts can carry only 1,200 watts. That Brit light switch effectively turns the whole circuit into a 10 amp maximum circuit. If the breaker is set to trigger only at 15 amps, then the 10 amp light switch may arc or burn out or start a fire in the wall when the load exceeds 1,200 watts. Now, I realize that most lighting circuits today don't get much above that, but you never know what some future resident might try to put on that circuit. Thus it's a very good idea to make the breaker equal to or less than the load capacity of all other components on the circuit, such as wiring and switches. Of course I'm not talking about load points here, that's a different matter.
The rationale for using 240 volts as a standard in Britain and Europe has much to do with a different philosophy as well as saving on conductor sizes. Copper has never been all that cheap. America in its abundance of natural resources decided that bigger conductors were an affordable tradeoff for increased insulation effectiveness. Europe decided to economize on wiring and other circuit components. But notice that standard British plugs have internal fusing, and things like lamp cords are not simply twin lead but have an extra layer of insulation around both leads. Twice the voltage makes that desirable bordering on necessary.
Bottom line, if you can't find a 10 amp breaker and don't want to use glass fuses (understandable), then ditch the Brit switch and go American.
The main reason that Europe uses 230V 50Hz is simply down to the fact that the European systems and US system developed in isolation and in parallel.
Many EU countries used to use 127V + 220V systems, with two hots and a neutral similar to the US, but this was largely abandoned in favour of a single 220V system after WWII (now nominally 230V to split the difference with the old UK 240V standard).
There isn't a particular logic behind why these voltages were selected.
Europe had multiple systems in the early 20th century, so I guess 220V 50Hz was the common denominator and it was also most suitable for using 3000W appliances without cumbersome fittings.
The US may well have standardised on 220-240V 60Hz too, however it didn't have that option as the rollout of electrical appliances was already very well underway and I home owners were unlikely to want to rewire. Europe had a big glitch due to WWII, so had a little more time to think about things and just opted eventually to use 220V for everything. The US standards were generally established quite early on when appliances drawing >1500W were highly unlikely to be encountered.
The safety arguments for 110V are relatively moot as there are generally very few problems with either system provided they're installed and maintained correctly and modern installations are very heavily RCD (GFCI) protected. In Europe, often every circuit has an RCD (GFCI) present.
230V also has a fire safety advantage as a 20amp circuit here can deliver twice the power without overheating where as undersized wiring systems in older homes in the states can sometimes be put under a lot of strain by modern appliances drawing a lot of power (Especially heaters, Air Con etc)
Double insulated everything in Europe was introduced in the 1970s and has been extended to everything. It's nothing to do with the voltage, rather to do with tougher regulations around appliance safety and to mitigate the risk of mechanical damage to cords. Older cords often were single insulated, and even zip cord before that.
Under the current framework of legislation in the EU and CENELEC (European Electrical Standards Body) guidelines, anything above 25V AC requires that. Anything below 25VAC is considered SELV (Safety Extra Low Voltage). So, use power cords if single insulated even used on 110V here would be illegal.
I fell foul of this in a university where we were using a piece of quite old equipment from a US installation that was operating on 110V. We had to replace all the cords and also not use NEMA plugs as they're in breech of Health and Safety regs too as the pins are not sheathed (i.e. you can touch the pins while inserting the plug). So we had to opt for the Euro/IEC 110V industrial plugs!
As for the switch, there's nothing particularly complicated about switches and it would work quite happily on 110-120V without any problems, but at a maximum of 10amps and it should be protected by a 10amp breaker, not by 15amps.
The mechanism and switch arc gap would be designed and tested for 230-250V so, it would be actually over engineered for 110V arcs anyway. There'd possibly be more of an issue with using a US switch on 230V than the other way around.
In the UK or Ireland where it is intended to be installed, it would be connected to a 10amp or 6amp breaker, and absolutely never higher.
An amp is a unit of current, wattage is the unit of power and voltage is potential difference which is comparable to pressure really in a plumbing circuit. All three are interrelated: Watts = Amps x Volts
So, if you decrease the voltage, the amperage goes up accordingly.
1000W at 230V = 4.35Amps
1000W at 120V = 8.34Amps
The current carrying capacity of the wiring, switches and other components is measured in Amps. The voltage is irrelevant. If you exceed the Amp rating on the device at any voltage it will possibly overheat, fail or even catch fire.
Also, please not this type of switch *MUST* be grounded as it's a metal body and should be connected to a back box which is also grounded and interlinked to ensure the screws are not live. Do not install it without a ground as you could give someone a very nasty shock if a wire ever became loose.
Also, if it's a 3-way switch it may have a slightly different layout than you're expecting.
BS (British Standard) light switches are also single pole, so they only have the hot wires present and only switch the hot. If you need to connect hot and neutral, this is not possible with this type of switch and it would not be normal to do so in the wiring system here.
Our neutral's connected to the ground at various points so it can usually be safely assumed to be 0V so there is absolutely no need to switch the neutrals on lights. In most cases, the neutral wouldn't necessarily even enter the switch box at all.
UK light wiring diagrams are linked below. They're possibly quite a bit different to the way it's done in the US.
Overall, I'd say while this is a perfectly good switch in every way, you're better off using a local switch that fits into your own system. There must be some chrome US-style switches you could use instead?
Using a British switch is just going to mean complications with breaker ratings, sourcing boxes and if it breaks you'll have to source a new British switch as US ones won't fit the BS-type boxes.
All of these systems are very good, but you are better not to take bits from one system and mix them with bits from another as you add a lot of complications that the designers of those systems did not envisage. They're called "systems" for a reason![this post was last edited: 1/11/2015-19:22]
Thanks guys for the input! I had a feeling it wouldn't work, but don't know enough about wiring to know for sure.
Artcurus: thanks for contacting the seller! I much appreciate your help.
Cadman: Yep, I think that 3-switch unit you posted will work perfectly. Now I just need to find one. My local hardware didn't have one so I'll try a larger store with a bigger selection. Thanks for the idea!
The reason we need the smaller switch is because the walls are going to be tiled soon. The 3-gang switch there now is halfway into the area to be tiled. We'll change to the switch type that Cadman posted, move the box into the tiled area, and call it good.
Now I just need to figure out how to make the switch below work for my garbage disposal! Hee hee hee....
A minor quibble: the probability of arcing goes up as voltage rises. It's probably close to negligible for the difference between 110 volts and 220 volts, but theoretically it's there.
A switch is a switch. It's a set of contacts that open and close. It does not care about the freq. of the current passing through it. It could be DC for all it cares. 10amps is a lot of current to switch. Unless you are running a massive chandelier or an iron or heavy equipment you will not be anywhere near that amount, simple lighting will be a fraction of that.
If the switch fits your needs and you have the proper box to mount it in I see no reason not to use it.
10 amps is certainly achievable, even at 230V if you have something like a set of recessed halogen spots! As more LEDs go in, lighting loads are getting smaller and smaller.
The risk with a 10amp switch on a 15amp circuit would be that in the event of a fault causing an overload that was less than 15amps, but more than 10amps the switch could burn out.
Sudsmaster: That's what I said : The switch would be over-engineered for 110V arcing, it's designed for 240V operation so the gaps would be big enough and mechanism fast enough to avoid any major arc issues. Although there's unlikely to be a hell of a big difference in design between US and Euro switches in reality.
I find NEMA plugs arc like crazy tho, even at 110V.
Never see any arcs with either BS1363 (British/Irish type) or "Schuko" (Continental European) type plugs even when plugged in at load.
I asked my cousin so i could understand this better but think its more confusing now?, heres what he said;
"There are 2 things to worry about: power (hear) and arc-gap. With DC, you will have a higher arc gap. So using AC, you would be better off. Often times they use mercury on DC contacts to make them wet so they do not burn up.
So, if you have 230VDC rating of 10 amps…. That’s 2300 watts (Power = Volts x Amp). Since AC is a sinusoidal wave, it’s will be 1.41414 x the amount of power capable (since a sine wave is .7.7x that of the full area under the power curve.
2300 watts = 120 volts x N Amps x .707
N Amps = 2300/(120 x .707)
N Amps = 27.38 amps
So you should be able to run around 25 amps through it. Now I have to ask, why? That’s a lot of power!"
[END]
Back to reality; So hes saying you can run 120v ac at 25amp through that 230v 10amp switch is what I understand. The ac/dc volt difference makes sense if your a welder. Dc welds have large arc, ac seems tight, smooth and quiet. bad example but thats all i got
My error! Thought most 230+v in europe were DC when I was there decades ago? If there using AC I don't get why it needs to be over 120volts? is it the cycles 60 vs 50?
I just put in an Adorne switch from LeGrand which at least looks like a European switch. I think the real issues is UL - if you sell or have need for insurance involvement it could cause problems.
If you really insist, you CAN get British switches made for the USA and Canada.
There is also Meljac, from France, now available here:
Thought most 230+v in europe were DC when I was there decades ago? If there using AC I don't get why it needs to be over 120volts? is it the cycles 60 vs 50?
