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Joined: Dec 2001
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This argument is almost as pointless as the German classic - where to put the live and neutral on an unmarked, non-polarised Schuko socket? There are no official regulations or even recommendations, yet the topic comes up again and again. My favourite explanation was that the live pin of a horizontally installed socket should be up in case the room floods... as if 19 mm made any significant difference!

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twh Offline
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Originally Posted by Texas_Ranger
My favourite explanation was that the live pin of a horizontally installed socket should be up in case the room floods
As I recall, there was once a Canadian rule, or a Sask. amendment, that required the neutral up on outdoor receptacles so that any debris that fell into the receptacle box would land on the neutral terminal. Around here, we're in more danger from falling dirt than rising water.

Joined: Apr 2002
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Up, down, neutral up or down didn't matter with 26" of flood waters from hurricane Sandy.

Heck, didn't matter much where it was 6-8' deep either, come to think about it.



John
Joined: Sep 2002
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It's a argument that where anyone says one way is correct & the other way is wrong, they are wrong. laugh I prefer ground prong up but mostly install down, it's a matter of preference or job specs IMHO.

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I have seen guys installing quads in a 4x4 say you should put one one way and the other the other way so the neutrals are next to the box and the hots are grouped together in the center. Less chance of a L/N or L/G fault.


Greg Fretwell
Joined: Jul 2007
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Hey guys, I apologize for pulling the proverbial pin on this grenade. I needed in my twisted way something to smile for at that time. It was solely meant for some electrician humor. Hope it did not upset anyone....

All kidding aside. My take came for my previous employer. He was adamant unless it put undue stress on the cord, the prong goes down when it is vertical and to the right when it was mounted horizontal. His explanation made the best sense of all I have heard in the past.

The ground prong on a plug is slightly longer then the blades in order for first make, last break when inserting or removing the plug. If the receptacle was wired properly wired and as time goes by, the tension wears off when the plug can dip down, pulling the ground prong out before breaking contact with the blades leaving the once protected equipment, unprotected. If the ground prong is mounted downward, the blades would break contact first before the ground prong thus maximizing safety.

In the horizontal configuration, if the plug would start to fall out, the ungrounded prong would likely pull out before the ground or grounded prong, again maximizing safety for the end user.

So being the wise guy, I asked him, "well, what about when the owner is too lazy crippled to bend over and pulls or pushes the plug at an upward angle?" his was reply was, "All we can do is show them how to use them properly by going straight in and out with the plug. we are not responsible for how they use them."


"Live Awesome!" - Kevin Carosa
Joined: Jun 2004
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As an engineering and geometric fact your former boss was wrong.

The prong standard was dimensioned just 'so.'

It's IMPOSSIBLE for the drooping plug to still have the active conductors engaged while the ground prong is engaged -- even slightly... even if you work the device out at an angle.

That's all part of the specification -- sort of under-the-hood -- that is not bandied about with civilians -- or even tradesmen.

The inventor/ designers foresaw that from the get-go.

You'll find the same dimensioning in all pin&sleeve designs. It's impossible to rock them, twist them, abuse them in any way such that the active conductors are not 'broken' (opened) first while the grounding/ bonding conductor is still engaged.

It's for the above reason that we just don't read about plug and receptacle calamities... cord cap failure -- at the cord to cap body -- that's another thing all together.

Towards that end, strain relief is ever more elaborate and refined. That design fault has only really been addressed in the last forty-years.

As for your last point: pin & sleeve cord caps are taking over the rough abuse market place. BTW, cripples are not the problem; angry, tired, wet, frozen field workers are the problem.

ANYTIME the weather is brutal, I'd spec out pin&sleeve connectors.

For those curious, it was the USAF that really put the push on for pin&sleeve connectors... back when SAC was rotating B-36 strategic bombers to Alaska and back. It was soon discovered that prior (Hubbell) twist-lock schemes -- no matter how robust -- were problematic in the Arctic. Dang ice was getting up and in. (Probably condensate, of course)

There were tales of bombers trapped on the tarmac while the ground crews tried to jumper up auxiliary power to keep the engines/ equipment/ interior within flight norms. Due to the mission $$$$ suddenly became no object.

Here and there you can still find photographs of the auxiliary power sets that have been rolled up -- in the nastiest weather -- to the big bombers -- running full tilt.

Curtis LeMay demanded that his bombers be able to get back airborne without any delay due to weather -- come Hell or high water. So these rolling gen-sets were scaled up to massive size. They kept the engines toasty -- and everything else.

The USN's approach to bad weather and electric power was the opposite: for as long as possible the USN tried to design their ships to run -- in extremis -- without any power at all. In the naval experience, the power system was most at risk from incoming shells and bombs. Pin & sleeve cord caps wouldn't correct that kind of glitch.

Of course, the USN is now introducing the hyper-electric navy. On board power generation is going through the roof. The big redesign of the nuclear carrier Ford is for a massively scaled power plant -- and a smart power distribution grid around the ship.

This scheme will not depend upon traditional fuses an switches. Instead, an 'Internet of things', a LAN of power, will constantly monitor this ship's power flow and shut off circuits that have gone south due to battle damage or whatnot.

This working scheme is destined to be civilianized for the next generation of high-rise skyscrapers. Buildings will become 'smart.'

That smells like a LOT of wire pulling in our future!

So



Tesla
Joined: Jul 2004
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It seems that the T/R receptacles have pushed the Line and Neutral contacts farther back than before and the plug has to be inserted within the last 1/4" to get power. I have wondered how much this affects long term reliability.
The ONE I have is used regularly with the vacuum so it will be a torture test for me.
This is also a USB outlet, another test I suppose.


Greg Fretwell
Joined: Mar 2015
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ppb Offline
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I personally have always put them down, then on a job one day a guy with years of experience who was once an inspector told me the ground prong should go up. I asked what was his reason ' and he said one example is if a man or woman with a long necklace leaned over to plug in something and the recep. was put in with ground down than a necklace could lean up against the hot side of the recep. that was partially plugged in and they could get grounded out? Not saying I agree , but it does kinda make sense when he put it that way. According to him there was a woman killed in Florida in the 90s when he was an inspector. He also had some other reasons that one just stuck out in my head the most.

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ppb Offline
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Correct me if I'm wrong they also had to be tamper proof, before residential tamper proofs. We wired a daycare and the height was 54 and the receps. were some kind of tamper proof recep. that was very expensive. Might have just been in the specs and not code not sure

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