Dual voltage sockets / circuits / appliance / transformer

[Ookysoft]

[ Admin:- please adjust title to something sensible for searches ]

Hi!

I have had housemates who are US Service personel or contracters working on the USAF bases here in Suffolk.

They left or have small appliances for kitchen use. [ smoothie makers, waffle irons, toasters, coffee makers etc.... ]

The normal course is to use a transformer on the worktop with the appliance. What I'd like to do is fit sockets for those appliances.

I can get ahold of face-plates, obviously wiring is not a problem but what style/type/size of transformer should I be looking for?

Usually these things turn on with a 'thump' - I'm thinking of isolating from the 240v ring so as not to leave the transformer 'hot' 24/7

Any thoughts/advice?

Thanks

 

[ban-all-sheds]

My advice is to bin them and get CE certified products designed for the UK market. They are clearly not the finest appliances known to man or they would not have abandoned them.

Plus there is no legal way you can install the necessary sockets.

 

[plugwash]

The small transformers typically sold for use with US appliances have two issues.

1: they are generally pretty small, if multiple appliances are likely to get used at once you probablly want something a bit bigger
2: they are typically autotransformers and often poor quality ones at that. When autotransformers fail they have a nasty tendancy of giving the imput voltage on the output.

Transformers made for construction site use are a better bet for a fixed 110V install IMO. They are generally higher power and being isolation transfomers do not suffer from the harmfull failure mode mentioned above. Downside is that the output is center tapped earth, that shouldn't matter for the vast majority of appliances but very occasionally you find one where it does.

You can get site transfomers designed for fixed mounting but they seem very expensive so i'd probablly just use a freestanding one in a cupboard.

Bear in mind that fitting US sockets will be a departure from BS7671, that doesn't mean it's illegal but getting such an install past building control (electrical work in a kitchen is notifiable) may be difficult.

As a compromise between fixed installation and small tranformers everywhere a site style transformer in a cupboard feeing an american power strip on the wall may be a reasonable way to go.

 

[ban-all-sheds]

Bear in mind that fitting US sockets will be a departure from BS7671, that doesn't mean it's illegal but getting such an install past building control (electrical work in a kitchen is notifiable) may be difficult.

So difficult as to be impossible, I reckon, as the departure would actually involve a contravention of BS 7671 that would imply a knock-on contravention of the Building Regulations requirement to make reasonable provision for safety.

As a compromise between fixed installation and small tranformers everywhere a site style transformer in a cupboard feeing an american power strip on the wall may be a reasonable way to go.

I don't agree that it is reasonable.

Reasonable is not making permanent provision for the operation of appliances not designed for our nominal voltage and frequency.

 

[ColJack]

and yet they're quite happy to allow dual voltage shaver sockets BAS?

and as you're quick to point out in other posts, BS7671 is only 1 way to show you've worked to a safe standard..
you may use other countries standards should you so desire.. although I'm not certain if that's limited to CENLEC member states..

it would be a specialist socket outlet so no danger of plugging in anything other than the specialised equipment intended for them..

it couldn't hurt to contact the LABC and make enquiries as to whether they would allow an installation to american standards.. or a part installation anyway..

MK even make 127V american sockets to fit on out standard single and double backboxes, though it does say "non UK" on the page.. do any other country besides us use the same type of backboxes?

 

[Hughie]

I've stayed in at least one recently-built (household name) UK hotel that provided a US socket alongside the usual array of BS1363/phone/modem/LAN outlets over the desk in the rooms.
Not sure how they wired it but it obviously satisfied a LABC.
H

 

[ban-all-sheds]

and yet they're quite happy to allow dual voltage shaver sockets BAS?

553.1.5 (ii)

and as you're quick to point out in other posts, BS7671 is only 1 way to show you've worked to a safe standard..
you may use other countries standards should you so desire.. although I'm not certain if that's limited to CENLEC member states..

It's not, but you can't mix'n'match, because in this case the rest of the installation would not comply with the NEC, so you couldn't claim to have worked to that.

it would be a specialist socket outlet so no danger of plugging in anything other than the specialised equipment intended for them..

553.1.4.

it couldn't hurt to contact the LABC and make enquiries as to whether they would allow an installation to american standards.. or a part installation anyway..

See above re mix'n'match.

I've stayed in at least one (household name) UK hotel that provided a US socket alongside the usual array of BS1363/phone/modem/LAN outlets over the desk in the rooms.
Not sure how they wired it but it obviously satisfied a LABC.
H

Part P does not apply to hotel rooms.

 

[ColJack]

different story for hotels etc.. different set of rules and guidelines too probably..

 

[ColJack]

great, I write a whitty and informative reply and while I'm doing it my internet crashes.. and this stupid window forgets it...

anyway, to sum it up..

553.1.4 Every socket-outlet for household and similar use shall be of the shuttered type and, for a.c. installation, shall preferably be of a type complying with BS 1363.

the sockets shown by that MK link are shuttered, and the above reg clearly says "preferably", so you can have other types or you wouldn't be able to use the round pin type either..

553.1.5 A plug and socket-outlet not complying with BS 1363, BS 546, BS 196 or BS EN 60309-2, may be used in single-phase a.c. or two-wire d.c. circuits operating at a nominal voltage not exceeding 250 volts for:

( i ) the connection of an electric clock, provided that the plug and socket-outlet are designed specifically for that purpose, and that each plug incorporates a fuse of rating not exceeding 3 amperes complying with BS 646 or BS 1362 as appropriate

( ii ) the connection of an electric shaver, provided that the socket-outlet is either incorporated in a shaver supply unit complying with BS EN 61558-2-5 or, in a room other than a bathroom, is a type complying with BS 4573

( iii ) a circuit having special characteristics such that danger would otherwise arise or it is necessary to distinguish the function of that circuit.

the american sockets comply with ( iii ) above as it would be a special circuit for the connection of 115V equipment and needs to be distinguished as such..

it also satisfies 553.1.2 since it's got provision for a protective conductor although that reg says it doesn't have to if it satisfies regulation 553.1.5

so now, at least as far as the socket-outlets go, I've complied with BS 7671 and don't need to "mix 'n' match" regulations..

 

[ban-all-sheds]

the sockets shown by that MK link are shuttered,

1) It doesn't say that in the technical specs.

2) Are the shutters operated by the earth pin? If not, is that OK? If so, what happens with 2-pin plugs?

the american sockets comply with ( iii ) above as it would be a special circuit for the connection of 115V equipment and needs to be distinguished as such..

Possibly.

so now, at least as far as the socket-outlets go, I've complied with BS 7671 and don't need to "mix 'n' match" regulations..

I'm still not entirely convinced.

Nor am I at all convinced that providing an installation which allows people to use equipment which would not be regarded as suitable to be sold here, and with motors designed for a different frequency, qualifies as being reasonable provision to protect persons operating it from fire or injury.

 

[ColJack]

not in the tech specs, but on the item page it says

K2252 WHI
2 gang
shuttered
(NON UK)
(FLUSH)

and on the specific american socket page it does..

doesn't have to be operated by the earth pin, some 13A sockets operate by rotating the shutters out of the way with the Live and Neutral pins..

like I said before, it couldn't hurt to ask the LABC if they'd be willing to accept it before he sends in his notification..

 

[ban-all-sheds]

and on the specific american socket page it does..

OK.

It also says that the (only?) standard it complies with is a Saudi one. Does that mean it it not CE marked?

Does it comply with the Plugs and Sockets etc. (Safety) Regulations 1994?

If the manufacturer claims that it does not need to comply with those regulations because it is not intended for domestic use then would using it in a domestic installation contravene 134.1.1? If a maker labels a product "Not for UK use", and you do use it in the UK it's hard to see how you have installed it in accordance with their instructions.

 

[ColJack]

is that what the SSA stands for then?
I was looking for it and thought it was american, no wonder I couldn't find it..

Electrical devices to which Part I applies
4.—(1) Subject to the following provisions of this regulation, this Part applies to the following devices namely any plug, socket or adaptor ordinarily intended for domestic use at a voltage of not less than 200 volts, to any fuse link which is suitable for use in any such plug being a standard plug and to any cartridge fuse link which is suitable for use in any other plugs and adaptors but does not apply to any electrical device specified in Schedule 1 to these Regulations.

so by my reconing, that doesn't apply to an american soclet designed to be used at a voltage of 115V?

it doesn't say "NOT FOR USE IN UK", it says "NON UK" refering to the fact that it's not a standard british plug..

I can't see a problem with it as long as they are on breakers that fuse down the 115V supply to 15A or less for each socket? Provision of a 13A Fused Switched Spur next to each outlet should suffice and also act as a means of isolation.

 

[TicklyT]

Just reminded me of a 100 mile round trip I made to a USAF base once to replace 'dead' modem.

When I got there, all I had to do was explain to an american airman that in this country, when presented with a 13 Amp socket, it is usual to flick switch toggles DOWN to turn appliances on

 

[bernardgreen]

Also to think about is that America supplies are 60 Hz ( cycles per second ) amd UK supplies are 50 Hz.

Equipment that is purely resistive ( heaters lamps etc ) this is not a problem but for items with wound transformers or motors the lower frequency of UK supplies can lead to overheating in the transformer or motor.

Induction motors will run slower so air flow in hair driers will be less and air temperature may be higher than it should be.

And US mechanical clocks will run slower in the UK.