Electrical Outlets

Some like the idea of a ground pin on top incase something falls it will hit the ground lug and not the L1.

Statistically, it's not a big advantage, but it's easy to do and it adds that tiny bit of safety to the mix of all the crazy things that happen in what is called life.

Ya, as an electrician, I've always installed outlets with the ground on the top. The whole falling stuff and all. The other side of the camp, says, put it on the bottom, in case it gets wet. The most important thing is that you actually have a ground. I've seen so many cases where they have mixed up L1 and L2.

"The most important thing is that you actually have a ground. I've seen so many cases where they have mixed up L1 and L2."

When one large facility was being built in Oak Ridge early in WWII a major error was made in the wiring of the crows foot outlets. The "identified screw was copper plated on the brass screw. Someone made the mistake that the bright brass screw was the identified terminal and the entire facility was wired bass backwards. As a result every piece of equipment had to be rewired the the operations organization before it could be use.

A new nightmare raised it's ugly head when the changeover to the new NEMA or round ground pin plugs were installed on equipment that hat to be used with the old receptacles during the process of change out.

"Ya, as an electrician, I've always installed outlets with the ground on the top."

But I have digressed from the OP. All of the power cords on all manner of things normally come with the standard straight wired 3 prong plugs, but an increasing percentage of them now have the cord coming off the plug at a 45 deg. angle so the cord can be close to the wall and point downward. Awkward if the receptacle is ground up.

Stan; why did everything run backwards? those were Australian outlets, very few electrical tools were 3 wire at the time of ww2, we simply took our pliers & gave a slight twist to the 2 male prongs to form a slight vee. perry

I asked the same years ago and the answer given was of wire or cable tension. Thinking this over a bit I would suppose the top position may cause less tension.

I believe that receptacles are more commonly mounted with the ground on the bottom for purely aesthetic reasons, that way they resemble little faces.

Often (at least in residential installations) the majority of the outlets are installed ground-down, while an inverted receptacle indicates that it is controlled by a wall switch.

Hello reefdiver

You seem to assume that we somehow know you are in the US.

In much of the world, domestic electrical outlets do not use round ground pins, instead using flat earth pins.

If you research history, you will find that the Flat Earth believers were correct centuries earlier, for those Countries later using that system.

Kind Regards....

What, now your gonna tell me that the world ain't flat? Sure looks flat. I have pictures that proves it's flat. The top of my head is flat.

Yep. The earth is flat.

(So are the live and neutral!)

It's also at the top. Otherwise any dripping water could get into the plug and cause havoc, especially at 240VAC.

Supplementary question - cables entering the plug at the bottom dangle nicely towards the floor with minimum strain. So why is the cable entry at so many battery eliminators and chargers at the top of the fitting, causing the maximum strain in the cable? Aaaaaaaargh!

What would prevent dripping water from entering the outlet regardless of where the ground prong was located?

Once water enters the outlet, regardless of where it enters, it will migrate throughout the internals and result in the same degree of havoc

"So why is the cable entry at so many battery eliminators and chargers at the top of the fitting, causing the maximum strain in the cable?"

I think that may have to do with the segregation of the high and low voltage wiring.

Just my uninformed guess

Is that because you have crew cut to remind you of Marine days? LOL

Regards;

Nadeem

I was once told about this: Years ago, electricians install the electrical outlet (in the U.S.) with the round ground lug on the bottom because it "points" towards the "ground" hence its easy to remember. Also, because of this practice, refrigerators and other household appliances came with the electrical cord with the ground lug towards the bottom. This way, the cord will come down naturally and plug into the outlet.

As of the ground lug install on top, the reason is stated by other post that if things are dropped on the plug, and if the plug is exposed, then its better to have the things dropped on the ground lug instead of live connection, thereby reducing the risk of a short circuit. In fact, this point of view is taking so seriously that the National Electrical Code has changed to reflect this so all new outlet installed in will have ground lug on top.

MidniteFigther

Are you KIDDING??? THEY CHANGED THE CODE? OVER THAT??? (shaking head here) let's see, if something drops on the plug and pulls it out hitting L1, no big deal unless it hits L2 at the same time. Then we have a quick flash, breaker snaps, then nothing.

So, lets change the code so people won't have to walk to the box and reset the breaker? We're talking about 110VAC here, not like it's going to hurt anyone.

I watched my grandfather wet his finger and stick in the light socket to check and see if it had power. Sure he got a shock about 50% of the time, but it wasn't life threatening or anything. No big deal.

-Your Honor, please instruct this witness to answer with only "yes" or "no"

-.......

-Thank you, your Honor!

-Mr. Labyguy, please answer with only "yes" or "no": Is your grandfather alive, is he?

now, that's funny..........

shocking...., just shocking! I've been looking to see if there is a code for the ground. I haven't found anything referencing right side up or down or which is which? Think I will finish out the back room with the outlet L2 on top. why not, it could catch on...?

No no...the trick is not to wet your finger... you simply just stick your big toe in the toilet, and then put your finger on in the socket hole.

Labyguy wrote "I watched my grandfather wet his finger and stick in the light socket to check and see if it had power."

Your grand father had the finger skin thicker than most people nowadays. He was a real man. He didn't have a direct line with his lawyer to sue the utility company for not having a warning sign at each point where somebody could contact the electricity. Imagine all the trauma experienced by somebody that gets shocked. It is enough to be off work for a week or two.

Our society is now ruled by wimps and lawyers. This is why we have to loose so much time trying to reduce the statistical risks to the point where it is a joke. This takes away a good part of the efficiency gained in the last century.

The goofy thing in the US is that all the consumer appliances are built so that the electrical cords expect "ground down." Net result is a loop of wire above the plug.

I've been twisting all the outlets in the house to "ground down" from "ground up" as I get to them. I had asked the electrician to do this but he said he couldn't because of code. One more pinhead rule that makes no practical sense.

I do especially like twisting the outlets with the power on. The tingle reminds me I'm alive. Ah well, life's little pleasures.

Greetings All,

Having done wiring of many voltages, AC & DC for over 30 years, this is the first time I have heard about installing an outlet upside down.

The reason that the ground pin is on the bottom is so that it is the last pin pulled out when the plug is pushed down.

I've seen where the ground pin is broke off in the outlet, where the ground pin was cut off the plug so it could be used in a 2 prong receptacle, etc.

Also had a steam fitter tell me he saw the drop-light with the light on all weekend, I had put it together, it was hanging in the sump pit, but something looked funny, he wiggled the cord and saw the water ripple above the light, there was a grounded outlet on the extension cord. But as usual on a construction site the electrician didn't have a ground hooked up to the distribution panel, only a neutral. Many houses have a ground to the water line, which corrodes and can loose contact when the pipe isn't sweating.

Just an observation... Looking through a few manufacturer's catalogs, I noticed that residential receptacles are built 'ground down' and hospital grade are built 'ground up'. Look at the nomenclature on GFI units.

From the U.S..... My understanding, too, is that with the advent of a grounding plug, the convention was established to install the outlet with ground up to prevent short circuits, should a metal object fall against the plug. I didn't hear about this "rule" until many years after I began to install outlets with ground down, just 'cause it made more sense to me at the time. Since I have encountered outlets installed both up and down, I have often noticed that electrical cords disengage easier from the ground up outlet, compared to the ground down variety. So, when I'm using a corded drill, etc. that is almost at the limit of its cord length, I am forced to return to the plug end of the cord to return it to the outlet many more times, if the outlet is ground up.

I wonder... if there has ever been a reported incidence of something falling against a ground down plug that resulted in a problem.

>>>>Just an observation... Looking through a few manufacturer's catalogs, I noticed that residential receptacles are built 'ground down' and hospital grade are built 'ground up'. Look at the nomenclature on GFI units.>>>>

I suppose one reason for the difference between residential and hospital receptacles is that, if you are rendered unconscious in an accident and wake up in a hospital, you can just look at the outlets and be able to tell where you are. "Oh, SH**, I'm in a hospital!"

Just look for the green triangle and you will be ok

Just incase they have you hanging upside down

Now that has to be the answer - what is now keeping me awake is that I have an outlet that was mounted horizontally and the ground pin is to the left - would it have been to the right if in a hospital?

I had heard that it started with the schools. To prevent children from placing or dropping a metal edged ruler on the prongs if a plug was slightly loose. If the ground is on top it is more difficult to make both contacts.

When i was an apprentice one of the guys was straitening metre lengths of TCW (sorry .. tinned copper wire) .. one rolled off the desk and fell between the mains socket and the plug.

the resultant boom blew the plug out, temporarily blinded him and nearly cut the pins on the plug in half. the socket also had to be replaced. this is 240V australian mains btw not 110v.

i have also done this at home with my old workbench in the shed. niow i refuse to have power points on the leading edge of the workbench.

so i would agree with the safety on dropped objects and i also like the last pin removed on the push down also.

our earth pins are a few mm's longer than the other pins as well, not sure if yours are or not ?

>>>>i have also done this at home with my old workbench in the shed. niow i refuse to have power points on the leading edge of the workbench.<<<<

I just tucked the outlets (power points?) a bit further under the edge of the workbench, so if anything falls off the bench, it misses the cords.

>>>>so i would agree with the safety on dropped objects and i also like the last pin removed on the push down also.<<<<

What's a "push down"?

What's a "push down"?

sorry to be vague, was a reference to post #13

have the earth at the bottom so its the last pin to be pulled out when the plug is pushed down.

Here in US, ground pins are also longer to ensure that ground is the first to "make" and the last to "break". Hospital construction in California is controlled by standards promulgated by the Office of State Architect, genereally a very rational outfit. The "upside down" receptacle requirement for hospitals comes from there, but they have not shared their reasons with me. I only wire 'em up. It has always seemed to me that devices used in any "upside down" receptacle have the ground pins on the wrong side of the angled cord, which should drape down when plugged in, but rerely do. It should be noted that "hospital grade" receptacles have printing and embossing that assume a ground up installation, while the reverse is true for common residential "U-ground" outlets. So perhaps a Mfgr could answer the "why?"...

<.....in US, ground pins are also longer to ensure that ground is the first to "make" and the last to "break".....>

This is also the case with UK/Eire/Singapore 3-pin to BS1363 and also the old BS546 5A round-pin standard, which can still be found occasionally. The 15A round-pin to BS546 has virtually disappeared apart from in theatre lighting systems in the UK, though it is standard in South Africa, among other places.

Here's some more information and some pretty pictures:

http://en.wikipedia.org/wiki/Domestic_AC_power_plugs_and_sockets

The round grounding pin on the NEMA 5-15 plug is required to be longer than the blades connected to L1 and L2, to ensure that the ground connection to any appliance is made before power is applied, and maintained until after power is interrupted. Most receptacles are installed about ten inches above the floor, so the plug will usually be inserted by someone reaching down from a standing position. Orienting the receptacle with the U-ground on top makes it easier to insert the plug, since the round pin can be partially inserted as a guide. It also reduces the likelihood that either the plug or the receptacle will be damaged when the plug is removed.

Hospitals are subject to frequent and rigorous inspections by the Fire Department, the Department of Public Health, and by the hospital's own insurance company.

If this orientation of those U-ground receptacles is required by the codes which have been adopted by the jurisdiction in which the hospital lives, it is likely that the hospital will try to maintain compliance with those codes. The reasons for changing a code are not always reasonable or clear, but if the code is changed, this change has the force of law.

'Most receptacles are installed about ten inches above the floor'

About 15"-18" above the floor general observation for CONUS unless on a flood plain (midwestern US) then could be 42"-60" above the floor. Note also the height in medical examination areas is about 40" above floor.

This is called dedicated grounding. The purpose of it is that you want to have a unique grounding path for those outlets strait to the main ckt breaker. This is different from the common ground share by many ckts in common. Hospital standarts are usually are more rigid than those for residential and comercial applications when it pertains to ground dedicated ckts. For better understanding of what I am taking about refer to articles 200, 210, 214 and 310 on the NEC. Hopefully this will anwser your question

Does it matter? as long as it is wired up correctly.

Do the Orientals put it to the side?

Nilli illigitimi carborundum!

>>>>Do the Orientals put it to the side?<<<<

I think they slant them. (Sorry, just couldn't resist. I harbor no ill feelings toward Orientals; in fact I love 'em as much as anyone else. Could easily have wed a cute Japanese josan, while stationed at Misawa Machi, but alas, I was too young.)

When I built my house 19 years ago, I installed all the outlets with the ground on top as I noticed that all industrial facilities had the outlets installed that way.

Since that time I have changed many of them to have the ground on the bottom as most right angle plugs are made such that with the ground on the bottom, the cord hangs down when plugged in.

And remember that Hospital outlets and residential outlets are NOT the same.

different code..

www.cooperwiringdevices.com

There is no code or rule that says it should be one way or the other...

There is no advantage to it being one way or the other.

All I recommend is that all the outlets in the house, bldg, etc. all be installed the same way

I am not an electrician however I have installed a few outlets. I always put the ground down on 15 amp circuits and the ground up on 20 amp circuits.

I once wired a university laboratory where the architect spec'd receptacles to be ground up below countertop height and ground down above countertop height, for no reason other than he "thought it would look neat."

I do know from personal experience that those little metal hooks used to hold christmas tree ornaments will get white hot in the time it takes a breaker to trip when they fall accross the hot and neutral pins.

The ground belongs on the left (my preference). I have an old house with ungrounded electrical outlets mounted horizontally. When I upgrade, I put the ground to the left.

does this make you a left winger instead of a conservative? A democrat instead of a republican? Danged if I know!

Calic0cat: Left winger? Not really - It keeps the power on the right. And to be extra conservative, or safe, it is covered by the neutral.

To maintain a proper balance, the power should beshared equally by the left and the right. Of course, nothing ever gets done then.

Of course. And hot water on the left.

yeah, I always get into hot water when I bring a left winger home....

It never ceases to amaze me how much discussion some topics receive. That's what makes CR4 so interesting! As far as which contact (neutral or ground) is connected to L1 first should not matter; since at the main panel they are connected to the same buss. Thus, they both represent earth. The safety ground is just that. In the event that the connected device experiences an internal short to the exterior casing a connection is made across the the protective fuse (circuit breaker) so that it can prevent some unknowing human from completing the circuit to ground. Often with very serious consequences.

I realize that it very late in the thread, but for some reason I felt compelled to toss in my two cents worth.

Up or Down? That reminds me, "Life is like a roller coaster: Up too slow and down too fast!".

Hi, reefdiver!

It does matter whether the ground is on the top or on the bottom.

The majority of grounded equipment in the hospital is often (and stupidly, for my money) equipped with a plug that is flat to the wall because it's believed that the oblique force exerted by accidental pulling on the cord results in fewer disconnections.

For this purpose, the ground post would be better suited on the bottom, not the top for two important reasons: 1. If the plug gets accidentally pulled out by a downward force, such as someone stepping on or tripping over its cord, the last thing in contact with the outlet will be the ground post. This is a safety feature.

2. The ground post is on the same side as the cord on properly grounded wire plugs in order to let the cord trail along the floor without a loop on the wall, so the hospital you saw seems to have got it upside down.

Flat plugs are, however, manufactured with the ground post either on the wire side of the plug or the unwired side of the plug, depending upon the manufacturer. If the cord is equipped with a flat plug, then the uppermost (easiest to reach) outlet has a ground to match the position on the majority of the equipment plugs, hopefully, being used in that hospital you visited. And for the reasons mentioned above, that ground should be on the bottom of the outlet unless the equipment it powers is hanging from the wall above the outlet with no extra length dangling to the floor, in which case you will see the ground hole on the top of the outlet. The problem with this arrangement is that any given outlet could be used for a variety of equipment. So in general, the ground hole should still be on the bottom.

The stupidity of the flat plug arrangement (as compared to the straight-on plug style) is evident when the corded side of the plug covers the second half of the receptacle so it can't be used. You may have run into the same problem on your computer's power bar where a flat plug literally prevents you from using the outlet next to it. Some hospital environmental designers are switching to single outlet receptacles because of this.

Mark

Hi Mark,

I am confused. All the outlets in my house are wired like in your middle picture, in the "undesirable arrangements" group. I would take your advice for granted, but in the same time I got this power cord, UL approved, with marking on the prong (N, L, and E) which matches all my outlets but doesn't the "normal arrangement". Occasionally I put my nose in some pieces of equipment, and if the live wire is connected to the chassis, I think that nobody would like to here what I am saying

Would you advise, please?

Hi, indel!

I recently bought two really nice grounded extension cords that were like your UL listed ones, upside down to the outlets (made in China, so they were inexpensive, and that's why I was happy with their purchase.). Unfortunately, they crowded my duplex receptacle outlets as a result. So I replaced them with UL listed ones that were reverse in arrangement (probably also made in China), and now I just use the upside down ones to run equipment on a jobsite. Not for any degree of permanency.

Since your outlets are properly installed, according to the blog I submitted, I guess you could do what I did.

Mark

Mark - Your "NORMAL ARRANGEMENT" appears to be abnormal with the neutral & hot reversed.

Hi, Snave!

Ay yi yi! That's what I get for using the plug face as a model to draw the receptacle. Almost dyslexic, eh? Gotta get me a drawing checker, or slow down or something.

Viewers take note. Hot should be on the left.

Mark

Hi Mark,

i cannot buy the receptical that you show as "recommended"

and even if I could, it would not work because all the grounded device plugs that i have seen have the bigger (neutral) lug on the left (if you position it so that it goes into the receptical with the ground lug on the bottom.

Hi, reefdiver!

I think I admitted my drawing error already in response to Snave, so now you can rest assured that the outlets you are buying here in North America (at least) are the same as mine and everybody else's. Just install them with the ground side down at home.

Keep those cords well plugged in to the wall. And try to not drop conductors over the poles to short them out if you can help it. LOL.

Mark

Same here!!

All the duplex outlets I have seen have the neutral spade side slightly larger than the hot spade side (as per the center drawing). They come from the electric supply place that way. None of my power cables would work in the box to the right.

Just remember that the black (hot) wire goes to the gold screw side and the white (neutral) wire goes to the silver screw side of the outlet (for those who are unfamiliar with the convention). And of course this is North American only.

Bill

Reefdiver, on the level now, did you really want and answer to your statement/question or did you just want to see if you could fill my email up? Please do not ask all of us if the glass is half empty or full !!! On the other hand, it is good to see that we all know a little some thing. SCORE ONE FOR YOUR STATEMENT/QUESTION!

Reefdiver, on the level now, did you really want and answer to your statement/question or did you just want to see if you could fill my email up? Please do not ask all of us if the glass is half empty or full !!! On the other hand, it is good to see that we all know a little some thing. SCORE ONE FOR YOUR STATEMENT/QUESTION!

dude , it wa a totally honest question.......i notice things like that.........i had alot of free time

It's called a monkey face w/ the grd. lug on bottom.Upside down monkey face is what you saw in hosp., It's safer that way because when a plug is hit from above by an object or small fingers, the first contact is made w/ ground, NOT the hot.

reygalindo is correct. Thus is also called issolated grounding amd often they are colored orange or green, but they come in other colors. Usually unbreakable plastic, nylon or ABS..and often have a green dot

They usually have a breakable link so you can chooze common grounding or isolated grounding. Breaking the link means the metal case and armoured cable and ground wire are not connected to the ground. The equipment ground is then run back to the true ground for that piece of equipment.

http://www.hubbell-canada.com/wiring/bryant/pdf/g/g10.pdf

http://www.thefind.com/instruments/info-hospital-grade-receptacle

The NFPA has taken no position on the orientation of the grounding hole. Article 406.9(D) addresses it only from the standpoint that the design of both receptacle and plug must be such that the equipment grounding connection be made before the current carrying connections. Thus it would be made first and broke last. Orientation is left up to installer or owner to decide. Molded cables, prefered grounding hole up for added protection, etc. are left up to owner to decide.