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My house has electric outlets in both orientations. Which one is correct? Should the ground hole be at the bottom or the top?

common electrical outlet (NEMA 5-15R duplex), ground hole on bottom

OR

common electrical outlet (NEMA 5-15R duplex), ground hole on top

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    I think this is possible to answer this question, and that Niall covered all the bases... ;)
    – Alex Feinman
    Commented Aug 10, 2011 at 15:43
  • Couldn't find any codes that deal with this, personally I like "socket boy" (ground down). If you have a 3 prong plug, it's usually more difficult to disconnect it by pushing down on it when the ground is down.
    – Tester101
    Commented Aug 10, 2011 at 16:24
  • It seems (to me anyway) they used to do ground up in the old days, but the electricians of the time never told their apprentices why. So the knowledge was lost to the ages.
    – Tester101
    Commented Aug 10, 2011 at 16:54
  • This question need not be local to the USA. Other sockets designs also have the same issue and in my travels I's seen sockets fitted in many strange positions. For example, China and Australia use the same shaped three pin socket but in China the earth is top where as Australia the code says earth is bottom.
    – Rincewind42
    Commented Aug 14, 2011 at 1:17

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The ground pin is usually facing down, and, if I recall correctly, when I installed some tamper-proof receptacles recently, the printing on them was right-side-up with the ground pin down. I believe it's also a requirement in some localities.

On the other hand, people supposedly install the ground pin facing up as a safety precaution: if you're falling or dropping something onto a plug that's not securely plugged in, you'll hit the ground pin first so there's no risk of a shock. If you've got both orientations within any one room, it's possible the installer didn't know what he was doing.

If your locality doesn't have a requirement for them to be facing down, I would just pick the orientation that you prefer and re-install the ones that are in the other orientation to match.

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    The printing is not always ground-side-down. I think it's just not standardized. See the Lowe's catalog of outlets: lowes.com/pl_Electrical+Outlets_4294821917_4294937087_
    – KeithS
    Commented Aug 12, 2011 at 21:54
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    In my house all of the outlets have ground pin down except for the switched outlets, those were installed "upside down", apparently to indicate that they are switched. When I moved in, I couldn't figure out why a few outlets were upside down.... until I plugged in a lamp and figured it out.
    – Johnny
    Commented Feb 6, 2015 at 21:19
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    It's a preference question (barring and local code requirement). Where I was able to, I installed my outlets horizontally to avoid issues where one extension/power cord was above another.
    – BrownRedHawk
    Commented Feb 6, 2015 at 21:45
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    With AFCI/GFCI breakers, the risk of the outlet shorting out from water dripping above is near 0. It should not matter what the orientation is for that purpose. Most wall warts are designed to have the ground pin at the bottom. In my old house the outlets were installed with the ground facing up and I had to duct tape one of the big wall warts to the wall to prevent it from falling out. It would have been fine if the ground pin was facing down.
    – Jason Hutchinson
    Commented Oct 27, 2015 at 20:30
  • mikeholt.com/…. An exhaustive discussion of the topic
    – Kris
    Commented Jan 16, 2020 at 4:38
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There are many transformers (wall warts), chargers, etc, that are polarized so the bulk of them is hanging down when the ground pin is down. If the outlet is installed with ground facing up, then these polarized wall warts will be facing up and often that will cause them to sit on the wall at an angle (since the center of gravity is higher than the plugs), exposing the prongs and creating a potential safety hazard.

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    Wall warts don't have to be polarized, and I can't remember the last one I saw that was; the diode/capacitor system that converts AC to DC ensures that one side of the DC will always be + and the other will always be -. As long as the circuit is continuous from one blade to the other, the diode will only let current flow in one direction. It would only matter which blade was hot if the adapter had a single-pole switch (in which case the switch has to disconnect the "hot" side).
    – KeithS
    Commented Aug 12, 2011 at 22:01
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In my home, I have both orientations. The sockets with the ground pin facing up are controlled by wall switches for on/off. The switches with ground plugs facing down are always hot.

This is in Las Vegas, NV, and I've seen that convention frequently here.

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    An interesting idea, but I'd rather use a recep of a different color to indicate it was switched.
    – Jay Bazuzi
    Commented Aug 11, 2011 at 4:58
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    The switched outlets in our house are split -- top half switched, bottom half always on. We just have to remember which ones they are!
    – TomG
    Commented Aug 13, 2011 at 2:32
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    @TomG: same in our house - most rooms are split that way. It is incredibly annoying, and I'm considering rewiring everything.
    – Alger
    Commented Aug 13, 2011 at 2:56
  • You can replace the split switched receps with single receps, so they don't have to be split.
    – Jay Bazuzi
    Commented Apr 6, 2012 at 5:35
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    Folks a split receptacle is just a normal one with a connecting pin taken off. Just put in a regular receptacle and connect it to the always hot or switched leg depending on your preferences.
    – Tim Post
    Commented Aug 26, 2012 at 15:18
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Ground pin down

In most situations the cord would be hanging down, which could cause the plug to tend to pull out in a downward direction. As a receptacle ages the contacts may lose a bit of their grip, allowing the plug to become dislodged. If the ground pin is down, it will be the last to lose contact with the with the receptacles contacts. If the ground pin is up, it could lose contact before the ungrounded blade leading to a potentially bad situation.

The ground pin being thicker and sturdier, can prevent the plug from becoming dislodged when holding the weight of a cord.

Ground pin up

If the plug was slightly dislodged, metal objects falling along the wall would short across the hot and neutral blades.

If the junction box were to fill with water, the water would reach the hot/neutral first. Which would short the receptacle and trip the breaker (Sounds odd, but I've actually heard this argument).

Conclusion

While both sides of the argument passionately believe they are right, there are no "official" standards on which orientation is correct. In my opinion, I follow the "make first, break last" principal. So I prefer ground pin down.

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  • Had a wire coat hanger fall on a partially unseated 220V heater plug. Of course it was installed in sleepy face mode, the flash burned half the contacts off, brass plated my fingernails and vaporized the hanger before the circuit breaker could blow. I was lucky, delivered a not very nice message about metallic bits storage above power sockets and learned to check for extraneous metallic garbage being stored from ceiling to floor above any socket.
    – Fiasco Labs
    Commented Aug 2, 2016 at 16:36
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That's a really good question. I have always considered "ground-pin-down" to be "right-side-up"; the plug looks like a face.

However, there are plenty of arguments to go either way; having the ground pin up is safer in terms of falling against a grounded plug, while ground-pin-down means that "wall warts" that have polarized blades or a ground pin can hang with their bulk positioned under the switch. Many AC adapters, though, have now gone toward either the "brick" style (with a short cord run on both ends of the adapter) or the "one-spot" (compact, and oriented either "outward" or "sideways"; either way the plug fits better onto a standard power strip).

Looking at Lowe's' catalog of 3-prong electrical outlets, it's a crap shoot as to which way each plug has been photographed. Whatever you prefer, plugs go into J-boxes either way, so you can do it however you like as the situation may call for.

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Years Ago While watching tv one day the tv set went off and so did some lights. I checked the fuse box and found that the fuse had blown. After replacing the fuse I sat down to watch tv again. In a few minutes the tv died and so did the lights. I checked and the same fuse had blown. Curious now I began my investigation around the house. In my twin 8 year old boys bedroom I found an outlet that had been charred. Further investigation revealed that part of a burnt penny was laying on the floor below. After questioning my two boys I learned that they were daring each other to pull the plug out slightly and dropping a penny in the slot between the plug and outlet. Having the ground down(normal) the penny would short the Hot and nuetral and blow my fuse. If the ground were up then this would probably not have happened. From then on I've been a ground up guy at least when kids are around.

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Traditionally, the ground pin is at the bottom. My grandfather installed them ground pin up because he believed a young child might otherwise perceive a "face" and decide to play with the outlet. I think, if you have a young child, just go ahead and get some outlet guards.

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  • And/or tamper resistant outlets.
    – keshlam
    Commented Sep 26, 2015 at 4:18
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I think the real answer varies not only by your local codes, but also if the work is commercial or residential.

I was always told that it is code (NEC) for commercial applications to have the ground on the top for the safety reasons listed in other answers. I almost always see them up at work and other places, so assume that is true. For residential, I dont think it is specified so it is up to the electrician's preference. In many cases, electricians that do a lot or commercial work, just keep it the same for residential out of habit.

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The explanation I was told was that if a metal face plate is used, the ground pin should be at the top. This way, if the plate were to become loose with a plug that is not all the way pushed in, the plate would contact the ground pin first as opposed to the hot.

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I was thinking that in a flood, there might be a possibility of electrifying the water until it hit the neutral( although the neut. spade is bigger) whereas with the ground pin down, the water would definitely make contact with the ground first and blow the breaker the moment the water touched the live spade! So if I'm wading around in a flooded house I'm less likely to get shocked. See I just added another scenario!

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  • I've never seen it in a code, but sideways (especially in a basement) you want the neutral lower in case it floods. IDT it really matters, but if you're going to pick a way, that's it.
    – Mazura
    Commented Nov 15, 2019 at 23:46
  • Flood water is already about as grounded as anything can get. It doesn't need to contact the ground pin in an outlet to get any more grounded.
    – brhans
    Commented Sep 18 at 1:16

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