"Upside-down" wall sockets

I've noticed in some new construction, like the new local community medical center branch of Brigham and Women's hospital near me, that the wall outlets are installed "upside-down", i.e. with the safety ground socket at the 12 o'clock position, rather than 6.

I assume there is a reason for this?

Reply to
bitrex
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If some bit of metal falls on it, it won't cause a short.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

Dunno. The orientation is not specified in NEC.

Indecision is the key to flexibility:

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Since I've recently spent a lot of time in hospitals ;-) it seem to be the standard in medical applications. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

In San Francisco, the rule is ground up for commercial installations, ground down for residential. Really.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

The ground-on-top thing has been the standard for light industrial since forever.

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Tim Wescott 
Wescott Design Services 
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Reply to
Tim Wescott

Sounds like there are a lot of ideal assumptions made in that chain of causality...

Reply to
bitrex

The thought is that if a piece of metal falls on the pins, it'll hit the ground pin, rather than across the hot and neutral pins. When I worked at IBM, all of the outlets were "upside down". I asked about it and that's the answer I got.

Reply to
krw

The thinkking comes from GFCI outlets or breakers.. if you drop a wire on the ground pin it'll connect to ether the N or L line causing the GFCI to detect unbalance in a very short time.

you still get exposed to live wires ether way. Having ground pin on the bottom will allow for L and N to come together but not the ground pin, in this case it can arc at the rating of the circuit breaker in the panel. This arc can get quite large (arc flash) and cause issues. Fires, burns etc. Could even weld something. Jamie

Reply to
M Philbrook

Wrong. It predates GFCI by a long time.

Reply to
krw

One more:

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

it may predate what I told you but these days that is what the reasoning is.. It has never been a rule for the orientation, you can put them at any angle however, in hospitals and places like it, it has become rule and GFCI use is the big reason for it, because it'll cause it to trip very eary and less damage.

If you want to argue about it I can likely throw some documentation your way about it.. I have to reference three different books when doing designs and that is in one of them. Local, State and Fed rules vary.

Actually, I won't bother to waste my time with you, because if you really were that interested you would research on yourown..

Jamie

Reply to
M Philbrook

Not sure what you think is going on. Nothing is foolproof, but this would improve the odds.

The US AC sockets are some of the crappiest around. The connectors in use elsewhere are *much* safer because they are not afraid to obsolete older wiring. I know of *many* houses built before three prong outlets in the US with 2 prong outlets (not even the type with one wide blade) which are grandfathered in. Talk about dangerous!

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Rick C
Reply to
rickman

Over here we have the "schuko" type which does not expose any pins and it is backward-compatible with the 2-prong version that existed before.

It is not ideal either, because it allows reversed connection.

The UK type does not have this problem and in general it has a lot of safety measures, but it is bulky. Preventing the exposure of pins has been an afterthought on that type (the pins are now partially isolated), and the same solution could be used in the US.

Reply to
Rob

I think that is an assumption. To shield the pins the way they do in the UK, the pins have to stop making contact with the socket pins when pulled out far enough to expose bare pins, or the plug would have to fall out of the socket. I don't know if that is well defined with existing sockets.

They changed the sockets not too long ago adding a shield in the socket to prevent anything being inserted into the socket pins unless a ground pin was inserted first. Of course this has to be backward compatible with everything else. Meanwhile a home can still have two pin sockets which are used with adapters which are supposed to be hard grounded but nearly never are.

A friend's window AC actually has a GFCI inline with the power cord because these are typically used in older houses which are exactly the ones that have the antique wiring.

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Rick C
Reply to
rickman

The solution may not be perfect, I don't know if it is in the UK, but it should help against the problem that the upside down mounting attempts to solve.

I have seen the US socket system and sure it is horrible. It is also used in Japan. When asking about it, people say "the voltage is not that high so it needs less protection than in Europe where it is 230V" but I am not buying that...

Reply to
Rob

It is extremely well defined that the earth pin is longer than the live/neutral, so that makes contact first on insertion, and remains in contact last on withdrawal. Inserting the earth pin also pushes the shutters across the live/neutral holes out of the way.

Decades after introduction a small sleeve was introduced on the live/neutral, since it had eventually been noted that small fingers could, with difficulty and the wind in the wrong direction, touch the live when it was still connected. (Optionally with the aid of an inquisitive knitting needle)

That is backward compatible with the sockets, of course.

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Shows internal wiring.

"Not to long ago" is more than half a century.

It wasn't backward compatible with the previous installations. I saw /one/ house with one of the old shutterless round-pin 5A sockets in ~1968, and they were obsolete then.

formatting link
Shows shutters in place during insertion.

Not in the UK; the only 2-pin mains connections are "shaver sockets"

Reply to
Tom Gardner

That is the case with the UK plugs and sockets. But with the US type, just grabbing the connector in an unlucky way will assure you contact with the live mains. (because the plugs are so much smaller)

For the "schuko" type plug there are unearthed versions that are much smaller, much like US plugs, but they always have those isolated sleeves on the pins.

Reply to
Rob
:

like type J, used in Switzerland:

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Bye Jack

Reply to
jack4747

I don't know the reason but I think it is bad idea. With ground at the bottom it is safer if you have a flood. Rising water will be "grounded" first before the line.

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Boris
Reply to
Boris Mohar

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