Anyone know about wiring UK wall switches in the US?

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zipdang

zipdang

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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.

http://www.ebay.co.uk/itm/Varilight...witch-Matt-Chrome-White-Insert-/131241846459?
zipdang-2015011101310302255_1.jpg
 
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...

cadman-2015011109042907016_1.jpg
 
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.

Kind Regards,

The Electrical Wholesaler Team
 
Sam is right.

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.
 
Something To Think About:

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]

http://www.ultimatehandyman.co.uk/how-to/light-fitting/light-wiring-diagrams
 
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....

http://www.grainger.com/product/SIE...d-Selector-Switch-WP171423/_/N-n5zZ1z13nv1?R%
zipdang-2015011120434105639_1.jpg
 
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.

 

Esp. in the damp British climate... lol...

 
 
Walmart actually has them

They are rated for

Voltage : 300VAC
Amps AC : 10

Best I can figure out (original langauge is German) it's a two position switch, first position on, second position, momentary)
 
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.
 
They would be rate for 10amps 250V AC Only.

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 ;)
 
It's absolutely not rated for DC and no switches or electrical accessories have been for many, many decades.

The switch would be rated for 10 Amps and tested at 250V AC Only.

I'm not sure why you're mentioning DC?

European countries all use 230V 50Hz AC.

There no way this switch is rated for use with DC. Are you planning to use it for lighting supplied from a battery or singing?
 
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:

http://www.lvl-usa.com/about-us.html

There is a North American, I think, company that makes concealed/drywall flush receptacles.

http://bocci.ca/collection/22/

http://www.forbesandlomax.com/invisible-lightswitch-usa/
 
Again, this is at your own risk. When in doubt, talk an electrician and go the professional route.

I just sent this to the seller on Ebay.

Just as an update. I talked to a master electrician here in the States . He's been doing this for over 40 years, in everything from oilfield to regular residential work.

When I explained the situation with this switch, he actually verified that it would work fine on 120 v. Here's why-

When voltage goes up, amperage goes down. The best example here is a typical central A/C unit. The condensing unit (the part that sits outside) operates on 220, for a total of about 30 amps on the cutoff. If it were 120, it would be a load of 60 amps for the cutoff. The same is true for clothes dryers here, and other high current applications. Some of the newer school buildings here are actually running 208-220 on lighting, with same voltage going to the wall switch.

In this case though, the switch is rated for 10A at 220 volt, but at 120, the current handling doubles, for a total of 20 amps. So in short, here, the switch is actually a 20 amp switch because of lower voltage.

Anyway, just some info.

Thanks again.
 
I'm not trying to be rude, but your master electrician is just plain wrong.

You are confusing current (Amps) with power (Watts)

The current carrying capacity of the device is a constant. You cannot change it, it's down to the physical design of the device.

If you increase the voltage, the amperage goes down for a given wattage (power)
If you decrease the voltage, the amperage goes up for a given wattage (power)

Lower voltage circuits require larger currents to deliver the same amount of Watts. So, 120V wiring is heavier duty than 230V to deliver the same amount of power.

The ability of a particular device to carry a current (measured in amps) only changes if you put in different sized conductors. Increasing the voltage just means you can transmit more power for that number of amps.

Basically, the British 10amp switch on a 120V US circuit can only deliver roughly 1/2 the number of Watts it would deliver in the UK.
The amperage remains absolutely constant as it's basically a description of what size current the device can safely switch and carry.
 
Reducing the supply voltage DOESN'T increase the safe current handling of the switch contacts!

This is easily explained by Ohms law, Power = Current^2 x Resistance. In this case the power is in the form of heat dissipated into the contacts based on current flow across the contact resistance.

The contacts are rated for a certain current based on their typical contact resistance and how much heat they can safely dissipate without degradation. Unless you can reduce the contact resistance, or increase the cooling of the contacts it is not wise to run the switch at higher then rated current. You may get away with it for a while, but contact resistance will climb with use and switch actuations and eventually it could fail.

I'm sure the 10 amp rating has a considerable safety margin in it. Also in most cases it is rare to use a typical household wall switch to switch more then a few amps of continuous current. I am reasonably certain that this switch would work perfectly at US supply voltages. I'm not sure I'd ever suggest someone do this though, although I might do it myself as then _I_ accept the liabilities for my own actions.

I think I'm with cadman though, I'd buy that cool looking Leviton triple switch and mount the box sideways.
 
Again, just saying what he said, and YMMV. (Your Milage May Vary)

If it were me, I wouldn't try it and stick with American switch, which there are similar ones available.
 
In the case of that toggle, they're referring to a motor load in which case they're derating current due to the device's inductive nature. A motor or coil without suppression can generate quite a nasty high voltage arc well above the source voltage which can destory contacts in short order. I think the assumption is made with residential switches that most loads will be resistive. -C
 
Switch voltage ratings

The reason a switch voltage rating matters is for insulation value with the switch in both open or closed positions (and to some degree as it transitions). The voltage has no influence on the the current that the switch can safely handle. Of course it is important that the switch not arc across its contacts or have leakage to the mounting etc.

With the exception of arcing, switch contacts fail due to heat which is generated by current flow across the contact resistance. It could be 5 volts or 500, but at 10 amps the heating of the contacts is the same.

Now all the above applies to to steady state operation with non-inductive loads. The switches that show reduced current for higher voltages are being derating due to arc over on break when switching reactive loads. This would be important for switching motors and transformers but not so much for switching lighting loads etc like the typical wall switch would.
 
Lighting load----not all of these are resistive.Lighting of the incandescent family is--but when the cold lamp is first started---high start current until the filament heats.Other forms of light Flourescent-reactive load becuase of the ballast.Same with HID lighting family-and their start current depends on the type ballast used.If the HID lamp has a Constant Wattage autoformer or isolated constant wattage transformer ballast-then the start current is low when the light is first turned on.As it reaches rated wattage the current increases.Now for the other HID ballast types-reactor(choke coil type)or autotranforfmer reactor types--the start current is HIGH when the light is first turned on-the wiring,switch,and breakers must withstand the start currents.This could last for several minutes.Then as the HID light gets to wattage on these types of ballast-the current than goes DOWN.
It has been found for large LED lights their start current is high,as well-but the start current is only momentary.Usual switches and wiring can handle it.
Light switches can be used on 120V,208-240V and lastly 277V(480V phase to neutral)There are all kinds of light fixtures-flourescent,HID and even LED that can run on 277V.The new LED yard lights installed at our site can run on 120-277V-no tap changing required.(Note 277V boxes are generally marked as such by codes)
Switching DC-this is normally done with DOUBLE pole switches to prevent arcing.You get more arcing on DC when it is interrrupted.I encountered this problem with the tool repair shop-there were many tools turned in with bad switches-these were used by--welder folks who were trying to use the tools on the 120V output of their genset welders-----This 120V is DC or crude AC.So the switches in the tools-grinders mainly had to be double pole.The double pole switch can be used AC or DC.Single pole on tools AC only.For the problem noted--I would use the American style switches-then you are safe--and keep code inspectors happy.They would frown on the foreign switches even though they may work OK.
 
Thanks to those who reinforced the concept that as voltage decreases, amperage must increase to deliver the same amount of power (watts). And more importantly, for clearing up the confusion that switches and wiring are rated for wattage and not amps. It is the amperage that is important in terms of circuit loading... And using a switch rated at 10 amps on 220 volts does NOT mean that it can handle twice the amperage on 110 volts... It can still handle only 10 amps... and on a 110 volt circuit it can support only 1/2 the total wattage that it would on a 220 volt circuit!

 

As for 10 amps being the maximum one might expect on a lighting circuit... well, that assuming the switch isn't also controlling a wall outlet, which is not uncommon at least at one time, where the wall outlet is intended to support plug in lamps. When I bought this place, it had two such circuits, one in the original living room, and another in the master bedroom addition. Fine and dandy, except I didn't know there might be limitations. I refinished the floors and at some point plugged in the floor sander into the switched outlet in the living room. It worked for a while and then stopped. I wound up taking apart the wall switch to find out why. It was a mercury switch and the load had caused the mercury bulb to overheat and leak out all its mercury. Yeah, I know, not a great thing to have, but I figured most of it went down inside the wall so it was pointless to worry about it. In any case, no guarantee that a wall switch will never handle more than the "expected" load. It's a hard and fast rule that every switch on a fused/breaker circuit must be rated at or above the breaker rating. So the breaker will open BEFORE the switch burns out.

 

Maybe someone will install a ceiling fan on the circuit. Maybe they decide they want a bank of heat lamps on it. Maybe that ceiling fan motor seizes up and starts to draw a lot more amps. Maybe they splice into the lighting circuit to support more wall plugs. Who knows?  That breaker on the circuit should then trigger before anything else burns out. Anything else is a disaster waiting to happen.

 

 

Oh, and I replaced that wall switch with a mechanical one rated at 15 amps... the same as the breaker for that circuit.

 
 

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