[the_nite_owl]

Just out of curiosity I was wondering about the orientation of three prong 120v outlets.
Most times I see outlets they are oriented with the ground prong down though sometimes I have seen them with the ground prong at the top.
I had asked about it once at a company I worked for previously and was told that it was safer in case something metallic fell down the side of the wall and squeezed between the plug end and bare metal.

Of course, when you are using AC/DC transformers for things like your computer speakers, cellphone chargers, etc, the ground up orientation of the outlet would force transformers with polarized plugs to be upside down and their own weight could tend to pull them away from the wall.

I have noticed that a number of the outlets in my house are ground up as well though many of the outlets in the house did not have grounds at all. I have been replacing those and testing for proper polarity and ground of course but it did get me wondering again if there truly was any good reason to orient ground up or even if it is a bad idea to do so.

[RickJ]

This is an old debate. The NEC does not speak of it - and the "safer way" explanation is a stretch.

Pick up nearly any electrical how to book and you'll notice any outlet pics are shown ground down... and this is the case on websites too.

[tkrussell]

Having the ground hole on the top was removed from the code few edtions ago. It use to be a requirement only in medical facilities, the reason was if a metal object, such as a scalpel, were to fall onto a plug inserted into the wall, and if the plug had come out some exposing the metal blades, the metal object would fall against the ground prong first, and most likely deflect the object from the live exposed blades, and prevent any chance of sparks. Sparks and anaesthesia do not mix well, or at least they use to explode easily.

And since most hospitals were wired by large union contractors, the practice spilled over to other installations over the generations. Methods performed by union electricians often became widely used in the industry.

Nowadays it is only a matter of taste. Not really sure why this requirement was removed, never really researched it.

[TheJollyOne]

I have wondered this question for years also, and when I pondering this and came across this web site. I concur that for me plugging them Ground Down works best for those bricks that the Electric devices use...

I like to have them look like a Smiley F☺ce~!

Then it occurred to me that if I were a small child with what appeared to be a face, I'd probably try to feed it's mouth, and then maybe poke one of it's eye's out...

So, if you have small children, then perhaps the Grounds Up, would be wise. But, if you don't have small children in you home, Ground Down, and don't be concerned about the Clown Face.

[stanfortyman]

Just teach your children not to stick things in receptacles and don't worry about smiley faces.

[tkrussell]

This brings up a good point not mentioned here often, or at all that I remember.

New to the National Electric Code 2008 Edition, per Section 406.11, that refers to Section 210.52, all receptacles in a dwelling shall be Tamper Resistant.

This, of course, to be clear, is ONLY FOR NEW INSTALLATIONS.

Code requirements is not retroactive, often referred to as "grandfathered".

You may upgrade any existing if desired, certainly will be required by code and inspector if the dwelling is "renovated". I quote that as this word can be open to interpretation.

For those with children and existing outlets, the prudent thing to do is use some sort of protection to keep the kids from sticking things into the outlets, child safety caps, etc.

Still no code on having the ground prong up or down. Install however you like.

[creahands]

On most appliances the ground prong on the top, thereby making the outlet more usable with ground on top.

Chuck

[tkrussell]

Could you show an example of this:

On most appliances the ground prong on the top, thereby making the outlet more usable with ground on top.Chuck

Best would be a photo of an example, or a detailed explanation of how a ground prong is at the top of most appliances?

[stanfortyman]

On most appliances the ground prong on the top, thereby making the outlet more usable with ground on top.

Chuck

I'd also like an example of this.

On most household appliances I see with a 90 degree plug the ground pin is on the bottom. Even at this it is usually just the washer, gas dryer and refrigerator.

[creahands]

Hi tk and stan

I stand corrected. The only plug I looked at was on my microwave and it is wired on the top. Checked the rest of app and they are all wired on the bottom.

The microwave may have had the plug changed because it is not a molded plug.

Sorry for the error.

Chuck

[stanfortyman]

You know what's funny. A lot of commercial appliances I see with right angle plugs do have the ground up.
Go figure.

[Charlie54]

For safety considerations, the hot prong is wired on top so if plug is stepped on or "falling out" the hot connection is disconnected first leaving the appliance still protected. This is true for vertical and horizontal installations.

[tkrussell]

Does not matter as the ground prong is intentionally longer than any other prong.

[liviupopa]

Make sens to be GND down side orinted.
The reason the GND is longer is that at the plog in to be the 1st to make contact so in case your tool is damaged (shut to the Ground) the protection will intrerupt the power before you gat electrocuted, and when you unplog the cord to be the last to be disconnected, or the cord is hanging in there (gravity) helf way in you need to have GND any time. So do make sens to be smailing.
Liviu Popa [email protected]

[Missouri Bound]

It's called a ground... install it closest to the ground (earth). And as far as plugs with the ground reversed, you see it often on wall mounted room air conditioners, and other appliances which are intended to mount high on the wall.

[JONtheBaptist]

According to NEMA anything 30 amps or greater should be installed with the ground on top for all 120 outlets. It is more convenient to install ground down in your home since most outlets are 15 or 20 amp breakers and manufacturer plugs typical orient the male end to have the ground down.

[tkrussell]

If NEMA has this requirement, please provide the back up.

Here is a somewhat lengthy discussion of the topic from Mike Holt:

Mike Holt Mike Holt Code Resources)

NEMA may have a recommendation, however, they do not dictate how receptacles are installed, that falls under NEC, and they do not have a requirement.

[Evil Kneivel]

The strange thing is that every major brand of AC manufacturers stamp all the printing on the face of the plug with the Ground hole at the top. So that if you install it ground down, all the writing is upside down. I always thought this meant that it was more "appropriate" to install them Ground up, I too wondered why the code does not seem to care.

Personally, I like them Ground up and that is the way I have wired my shop. :-)

Cheers