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Topic: light switch orientation

David Buckley
Jedi Master Film Handler

Posts: 525
From: Oxford, N. Canterbury, New Zealand
Registered: Aug 2004

posted 08-30-2015 04:08 PM

Also amusingly, in the context of light switches, what an American calls a "three way" the rest of the world calls a "two way".

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 08-30-2015 05:08 PM

Why do the UK outlets have switches in them? Are they not mounted near the baseboards on the walls where switches would be inconvenient to use?

In the US, it is common to have a wall switch near a door that controls an outlet on the wall. The idea is that a lamp would be plugged into that outlet and one could simply flip the wall switch when entering the room in order to turn on the light. This works fine unless someone decides to plug, say, a clock (or anything else that requires constant power) into that same outlet.

Having said all of this, the standard US "Edison" style outlet (NEMA 5-15P/5-15R) is pretty awful, as it allows one to touch both the hot and neutral pins when plugging something into the outlet and it also has no locking mechanism. Also, older outlets are not polarized and have no ground pin, which means that it is possible to plug in a lamp in such a way that the socket will be live even when the switch is "off." The UK connector design is far superior.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 08-30-2015 05:41 PM

Steve: Only had to happen once to me on the Christie rectifier cover. I mounted a long screw with a spacer to block that happening: 3/4". Tried to get Christie to move the outlet location.

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 08-30-2015 05:48 PM

quote: Scott Norwood
Why do the UK outlets have switches in them?

You can buy ones that don't, but in practice you don't see many of them in a typical home. In my last UK home before emigrating, the only one was for the hot water boiler's power supply. I guess a switchless outlet was installed there because it was intended to supply just the one appliance, that would be always on.

But I agree that the switches were largely pointless. Whenever I was away from home for a significant length of time, I always pulled the plugs right out for everything that didn't need power while I was away, anyway.

Another difference I've noticed is that outlets with built-in GFCIs (known as a residual current device, or RCD, in Britain) are widespread in the US - indeed the National Electrical Code requires them in rooms that have a running water supply. In Britain, although plug-in RCDs are common and easily available (i.e. you plug the RCD into the outlet and the load into the RCD), outlets that have them built-in are almost unheard of. I never saw one in B & Q (the British version of Home Depot).

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Mark Hajducki
Jedi Master Film Handler

Posts: 500
From: Edinburgh, UK
Registered: May 2003

posted 08-30-2015 06:34 PM

quote: Leo Enticknap
Another difference I've noticed is that outlets with built-in GFCIs (known as a residual current device, or RCD, in Britain) are widespread in the US - indeed the National Electrical Code requires them in rooms that have a running water supply.

Before 2008 no mains electrical sockets were allowed in bath/shower rooms in the UK with the exception of shaving sockets with an isolating transformer.

The regulations have become more flexible over the years allowing RCD protected sockets in some areas of bathrooms.

The UK regs tend to be more protective than most countries insisting on plugs/sockets which are more substantial than most countries have fused plugs and earthed (an earth pin is required to allow the insertion of a plug, some dual insulated appliances have a plastic earth pin).

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 08-30-2015 09:58 PM

quote: Mark Hadjucki
Before 2008 no mains electrical sockets were allowed in bath/shower rooms in the UK with the exception of shaving sockets with an isolating transformer.

Plus the light switch has to be a pull-cord, not a switch you actually put your finger on. The principle was that your potentially wet hands should not go anywhere near the mains current.

Maybe a reason for the more safety-conscious design of British electrical fitments is the higher voltage (240 when most of them were designed, 230 now) than in the US? My understanding from the medical experts on this is that a 120v shock is highly unpleasant but is unlikely to cause serious injury or death, but 230 stands a very good chance of killing you.

If I remember correctly, 2007 was when the US National Electrical Code was revised to require GFCIs/RCDs in all rooms that have a water supply. Before then it was just the bathroom and outdoors. In a typical American suburban home that can mean the entire living room/kitchen area if it's open plan, plus the bathroom(s) and possibly the garage as well, if the washing machine is in there. Normal light switches are allowed in bathrooms, though, plus outlets as long as they have a built-in GFCI.

When we moved into our current house, built in 1984, none of the outlets were GFCI-protected whatsoever apart from the one in the back yard! The surveyor's report flagged up that some of the wiring was aluminum and that aluminum wire joined to copper is very dangerous and needs fixing immediately. We hired an electrician do this, who tipped us off about the new GFCI regulation, which wasn't there when the house was built, but is now. I replaced the outlets myself. Rather than mess around trying to figure out where they were required and where not, I just got a contractor's pack of 20 from Home Depot and replaced all the outlets in the house.

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Lyle Romer
Phenomenal Film Handler

Posts: 1400
From: Davie, FL, USA
Registered: May 2002

posted 08-30-2015 10:27 PM

quote: David Buckley
Also amusingly, in the context of light switches, what an American calls a "three way" the rest of the world calls a "two way".

More amusingly is that they are really four way.

UP-UP
UP-DOWN
DOWN-UP
DOWN-DOWN

You could argue that UP-DOWN and DOWN-UP are the same and therefore the name of "three way" is correct. I don't know how you can get "two way" out of that configuration. A regular switch is "two way" since it is open and closed.

Just to throw in some more semantics, you "close" a switch to "turn the lights on" yet some people say "close the lights" to mean turn off the lights. I guess if the action is done with covers (as some metal halide arena lights do for instant on/off during pre-game) then you are literally closing the lights.

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Stephen Furley
Film God

Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002

posted 08-31-2015 03:12 AM

quote:
- posted 08-29-2015 05:50 PM Central (GMT -6:00) (11:50 PM Local) Profile for Steve Guttag Email Steve Guttag Send New Private Message Edit/Delete Post
With respect to the receptacle, every NEMA diagram for the 5-15 (or 5-20) will show the ground pin down (likewise on the other straight blade NEMA drawings).

The reason I heard that the practice on installation was changed was due to the potential for a metal wall plate to come off and land on hot and neutral. With the ground pin up, you have a 50/50 shot that the short will go between ground and neutral or ground and hot.

Steve, it always seemed unlikely to me that something would fall between a plug and the receptacle; I hadn't thought of a metal wall plate. Over here we don't normally have wall plates like you do. Something similar is sometimes used for switches, mainly for large boxes with a large number of switches are installed, or switches of different types in the same box, e.g. Where some are key switches are required.

With normal 13a sockets we don't mount the socket in the box, and then attach the wall plate, the plate is a permanent part of the socket and the whole thing is secured in the box by two screws.

Also, in the UK it has been a requirement for many years for both current-carrying pins to be shielded over part of their length, so that bare metal cannot be exposed when live if the plug is not fully inserted. I have never seen anything similar on any type of Nema plug, though it is required in Austrailia, where the blades are the same size as those on a 15 or 20 A Nema plug, so it is possible on such thin blades to remove enough metal for part of their length to enable the shielding to fit. It does however make the blades very thin, and liable to bend.

Similar shielding is also required in Italy, while in France and Germany the socket is by design recessed, so the plug body prevents access to the pins when they become live. More recent Swiss sockets also have to be recessed, though older ones were not.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 08-31-2015 06:48 AM

Yeah, in the US, one has always had the ability to shock themselves. There is plenty of exposed metal once the prongs have been electrified to touch them. Note, the ground pin is longer so there is never a time when the ground pin isn't inserted when the hot pins are.

Aside from the GCFI changes...about all I see different now on SOME outlets is that that there is a cover to the hot pins that doesn't open until the ground pin goes in.

quote:
When we moved into our current house, built in 1984... The surveyor's report flagged up that some of the wiring was aluminum and that aluminum wire joined to copper is very dangerous and needs fixing immediately.

Now those statements shouldn't be true together. In 1984, aluminum wiring shouldn't have even been available in typical branch circuit sizes of 20A or less (12awg and smaller). By the late 1970s, aluminum wiring should have been all but gone in new work.

Aluminum remains the wire of choice for high voltage/long distance lines...it is MUCH lighter than copper. It isn't that aluminum isn't a good conductor it is that it can have issues with what it is connected to if the connection is not designed for aluminum.

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

posted 08-31-2015 10:14 AM

I had a new house in the late '60's with aluminum romex. What a horror. When used with outlets that moved around a little, the aluminum would crack instead of flex as copper would. Also, all the plugs were wired daisy chain style using the push in connectors on the back. The only thing that prevented a fire was I had plastic child proof caps in the outlets and one melted alerting me to an issue.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 08-31-2015 04:48 PM

Properly installed aluminum romex was perfectly safe the trouble was many people didn't use al rated devices or made connections improperly

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

posted 08-31-2015 05:48 PM

I'm not sure the correct type of aluminum was used for Romex. Seemed mighty brittle to me. After all, the main reason contractors used it was to save a few $$ on the cost of house wiring. Lets say it was $50.00 on the total cost of a new house. Hardly worth it.

House wiring is very low tech and cheap with plastic junction boxes that won't hold up to any significant heat.

Even in industrial use, you don't see it used in small gauges, 10 to 14 for instance.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 08-31-2015 09:33 PM

Sam is correct on all counts on this one. Aluminum was used for cost reasons in internal wiring (unlike for power distribution where aluminum has benefits due to not only cost but weight). Aluminum is definitely more brittle to work with too. And yes, with the proper terminations, Aluminum can be safe (it is used as the feeder from city power to many/most dwellings. However, in its "heyday" for domestic wiring, what was being connected was NOT designed for it so many outlets overheated.

Now it is a tainted product that nobody would want and it is still more dangerous to use than copper since it requires more care/attention than copper and in most home applications, the cost benefits are not there. I'd think most residential codes no longer allow it on branch circuits. That said, I see the AL/CU on most receptacles signifying that it is designed for Aluminum/Copper.

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Gerard S. Cohen
Jedi Master Film Handler

Posts: 975
From: Forest Hills, NY, USA
Registered: Sep 2001

posted 09-02-2015 03:03 PM

New York City code does not permit Romex cable for houses nor for commercial use. I think BX cable was required since before any of us were born. Although its metal shield provides grounding, as it is connected with all metal outlet and switch boxes and also to a water pipe closest to the entry water main, code now requires three copper wires to run through the armored shielding (iron or steel galvanized with zinc). The green wire serves as an additional ground.

I think it was in the 1920's that George Herriman's Krazy Kat first used the expression "Turn on the Dark", a phrase that served as sub-title of a popular super-hero Broadway play.

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David Buckley
Jedi Master Film Handler

Posts: 525
From: Oxford, N. Canterbury, New Zealand
Registered: Aug 2004

posted 09-02-2015 04:02 PM

I believe Chicago also has this attitude; all wiring in metal.

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