# Ground pin up vs Ground pin down



## Cholly

I've often wondered why the AC outlets in commercial sites (business offices, medical facilities, restaurants, etc.) are oriented with the ground pin up and in homes they are installed with the ground pindown. The NEC has no rules stating the orientation of 3 pin grounded AC outlets. However, residential outlets for the most part are oriented with the ground pin down, with the exception of outlets controlled by a switch, in which case they are usually installed with ground pin up. In commercial installations, for some unknown reason, outlets are almost universally installed with the ground pin up.

Interestingly, flat plug extension cords, "wall wart" transformers and many other products designed with residential use in mind, are designed for use with the live (wide) blade on the left, which corresponds to ground pin down.

Of course, there may be some local codes that specify orientation.


----------



## James Long

Here is a nice collection of reasons:

https://www.mikeholt.com/technical.php?id=grounding/unformatted/9-23-99&type=u&title=Receptacles%20-%20Ground%20Up%20or%20Ground%20Down?%20%289-23-99%29

According to that site IEEE Std. 602-1986 (Electric Systems in Health Care Facilities) recommends ground up, but it seems that beyond that it is personal preference.


----------



## Rich

Cholly said:


> I've often wondered why the AC outlets in commercial sites (business offices, medical facilities, restaurants, etc.) are oriented with the ground pin up and in homes they are installed with the ground pindown. The NEC has no rules stating the orientation of 3 pin grounded AC outlets. However, residential outlets for the most part are oriented with the ground pin down, with the exception of outlets controlled by a switch, in which case they are usually installed with ground pin up. In commercial installations, for some unknown reason, outlets are almost universally installed with the ground pin up.
> 
> Interestingly, flat plug extension cords, "wall wart" transformers and many other products designed with residential use in mind, are designed for use with the live (wide) blade on the left, which corresponds to ground pin down.
> 
> Of course, there may be some local codes that specify orientation.


I've been looking at receptacles since I was an apprentice electrician and there seems to be no rhyme or reason to how they're installed. I even called the Hubble company (we used many of their electrical devices in our plant, good stuff,very reliable) and asked them how they should be installed and they told me, "Think of faces" when installing them. Two eyes and a nose. When I asked why, they told me it just looks better. Have to agree with them. I just spent 6 cheery days in a hospital and every hospital grade (red) receptacle I saw was installed like a face. I've always installed them that way, both at work and in homes.

Rich


----------



## peds48

I was once told that the best practice was to install them with the ground pin up. Reasoning was that if the plug was not inserted all the way and the outlet was install ground pin down it could create a short if something metal where to fall on the top blades. Of course the probability of this happening are minimal but they are there nonetheless. 


Sent from my iPhone using Tapatalk


----------



## SayWhat?

Oddly enough, in a box I'm installing outside where I'm using three duplex outlets, I'm doing a mix; one up, two down. Allows flexibility if I add a timer or other device that has the pin up and cords that have pins down.

.


----------



## inkahauts

peds48 said:


> I was once told that the best practice was to install them with the ground pin up. Reasoning was that if the plug was not inserted all the way and the outlet was install ground pin down it could create a short if something metal where to fall on the top blades. Of course the probability of this happening are minimal but they are there nonetheless.
> 
> Sent from my iPhone using Tapatalk


Sounds as useful as the stupid gfi circuit breakers they force people to use in some places now for fear that a static electric discharge might start a fire because it happened once.


----------



## AntAltMike

inkahauts said:


> Sounds as useful as the stupid gfi circuit breakers they force people to use in some places now for fear that a static electric discharge might start a fire because it happened once.


I know this is an ignorant thing for me to say, but I'll say it anyway: Every time I have ever gotten a jolt, it was because my "other" hand was touching something that was grounded.


----------



## peds48

inkahauts said:


> Sounds as useful as the stupid gfi circuit breakers they force people to use in some places now for fear that a static electric discharge might start a fire because it happened once.


Thank goodness for UL labs! without them we would be that much more unsafe.....

Sent from my iPad using Tapatalk


----------



## Nick

AntAltMike said:


> I know this is an ignorant thing for me to say, but I'll say it anyway: Every time I have ever gotten a jolt, it was because my "other" hand was touching something that was grounded.


 :flaiming

Don't do that!


----------



## trh

AntAltMike said:


> I know this is an ignorant thing for me to say, but I'll say it anyway: Every time I have ever gotten a jolt, it was because my "other" hand was touching something that was grounded.


Have you watched the 'electricity can hurt' video posted by cholly in the OT?


----------



## njohn2121

As a consulting/specifying electrical engineer, I have been asked this before by some building owners and maintenance personnel. The reason peds stated above about something falling on the exposed prong is what I have most often heard as well. When I was working as an electrician, I always despised seeing the ground prong up. No real reason, just a preference. 

The company I work for now has ground prong up written into our standard receptacle installation specification. I suspect this was added from a standard spec like CSI or other that wrote it with the ground prong up to cover themselves on the health care facilities and it was left that way to cover any liability for any facility. Because of this, it has basically become standard practice to install it up in a commercial environment, unless directed otherwise. 

In a house, stock specifications are rarely used and many homeowners tend to complain that prong up looks strange and they want it changed. Change comes hard for so many of us!


----------



## tenpins

We recently completed/ moved into a new built home and during our walk through w/ the Construction Sup; he explained that the UP prong indicated which outlet was controlled by the on/ off switch on the wall.


----------



## AntAltMike

tenpins said:


> We recently completed/ moved into a new built home and during our walk through w/ the Construction Sup; he explained that the UP prong indicated which outlet was controlled by the on/ off switch on the wall.


That is a clever idea only for as long as someone remembers or realizes that.


----------



## Rich

tenpins said:


> We recently completed/ moved into a new built home and during our walk through w/ the Construction Sup; he explained that the UP prong indicated which outlet was controlled by the on/ off switch on the wall.


That sounds like a good idea.

As far as worrying about something jarring the plug loose and having something hitting the hot and neutral prongs, what do the folks who actually believe that's a common occurance suggest about using a two pronged plug? like the plugs on the HRs? There's a lot of electrical devices out there that use two prong plugs (without a ground prong).

Rich


----------



## James Long

I have seen outlets wired where one outlet is hot and the other outlet is switched. A hotel I stayed at last month had switched outlets and had the TV set and microwave plugged into the switched outlets (there were not enough outlets for the "always on" equipment.


----------



## Rich

James Long said:


> I have seen outlets wired where one outlet is hot and the other outlet is switched. A hotel I stayed at last month had switched outlets and had the TV set and microwave plugged into the switched outlets (there were not enough outlets for the "always on" equipment.


Pretty common to split the receptacle so that one is controlled by a wall switch and the other one is always hot. I do like the idea of putting them upside down so that it is easier to tell which receptacle is controlled by a wall switch even if it is split.

Rich


----------



## peds48

Rich said:


> That sounds like a good idea.
> 
> As far as worrying about something jarring the plug loose and having something hitting the hot and neutral prongs, what do the folks who actually believe that's a common occurance suggest about using a two pronged plug? like the plugs on the HRs? There's a lot of electrical devices out there that use two prong plugs (without a ground prong).
> 
> Rich


same can be said about a car without airbags. Some devices don't have all the safety features built in.

Sent from my iPhone using Tapatalk


----------



## NR4P

I also heard that Commercial buildings did this as a practice to save money. Wires drop from above and it saves pennies of ground wire times thousands of outlets. Don't know if it's true, just another reason.

BTW, I don't buy the ground up as a real safety issue meaning it may stop arching etc. I think that is an afterthought for a reason, not a design issue.
If we really cared, we would go to the European model where the plug is actually recessed into the outlet so if it's sticking out a bit, it won't work.


----------



## njohn2121

NEC requires 6" tails at all outlet locations. So it wouldn't matter if the ground was up or down to try and save wire length. Also, when the box is bonded, the ground usually needs to be a little longer than the rest of the conductors. 

I don't buy the ground up as a safety thing either, but it seems to be a pretty common explanation.


----------



## P Smith

Seen around [British] all outlets installed groung pin up. No exclusion. Perhaps the rule slipped into US soil not being included into standard?


----------



## armophob

I always looked at the ground prong at the bottom like a drip loop on a wire.

If something liquid starts to make continuity, give it a direct ground to pop the breaker.
Instead of something else below that would cause a fire.


----------



## Nick

Just a personal preference, but I like the ground hole down because
it gives the outlet look a surprised "Home Alone" - like expression. :eek2:


----------



## P Smith

SOme good reading here https://www.mikeholt.com/technical.php?id=grounding/unformatted/9-23-99&type=u&title=Receptacles%20-%20Ground%20Up%20or%20Ground%20Down?%20%289-23-99%29

What I like in BS1363 standard is summarized here http://gizmodo.com/5972640/why-power-outlets-look-so-weird-in-other-countries


> AnaerinAndrew Tarantola
> 1/08/13 5:47pm
> http://gizmodo.com/5972640/why-power-outlets-look-so-weird-in-other-countries#
> Personally, I'm a very great fan of BS1363, for a number of reasons.
> 1. Large conductors for better power flow without overheating or sparking
> 2. Each outlet is fused for safety
> 3. Each plug is ALSO fused (and only to the required load) for safety
> 4. Each outlet can be individually power controlled, to help control vampire loads
> 5. Outlets are shuttered, so inquisitive young children can't insert a pair of keys (or something similar) and electrocute themselves
> 6. The outlet will not open without an grounding pin inserted, making the ground pin mandatory, and ensuring it is the first contact to make and the last to break
> 7. The power and neutral pins are isolated, so even with the plug partially inserted you can't insert a key or wire to create a short across them
> 8. The cords come out at 90 degrees (flat against the wall, and pointed down at the ground) so they don't get snagged as easily, and so they fit behind appliances and cabinetry easier
> 9. Plugs have built-in, deep, grips to make it easier to hold and remove, especially for the elderly
> 10. Plug pins are (incredibly) sturdy, so they don't get bent out of shape if mistreated (Yes, this makes them uncomfortable to step on, almost worse than Lego)
> 11. Sockets are standardised as to which way they're mounted (Ground pin on top)
> 12. Size of the plug means that typical Wall-Wart power supplies don't cause nearly so many blocking issues as they do with other (US) plugs.


----------



## Rich

NR4P said:


> I also heard that Commercial buildings did this as a practice to save money. Wires drop from above and it saves pennies of ground wire times thousands of outlets. Don't know if it's true, just another reason.
> 
> _*BTW, I don't buy the ground up as a real safety issue meaning it may stop arching etc. *_ I think that is an afterthought for a reason, not a design issue.
> If we really cared, we would go to the European model where the plug is actually recessed into the outlet so if it's sticking out a bit, it won't work.


I've never seen it happen. If it was an actual problem, I'm sure it would be in the NEC.

Rich


----------



## P Smith

Rich, read at that site long reasoning for "up or down", you'll find why many electrician inclined to follow British standard BS1363...


----------



## Herdfan

inkahauts said:


> Sounds as useful as the stupid gfi circuit breakers they force people to use in some places now for fear that a static electric discharge might start a fire because it happened once.


I think you mean AFCI and yes, they can be a PITA. I think before it is over, every circuit in a house will have either an AFCI or GFCI breaker.


----------



## scooper

I think requiring every breaker to be AFCI or GFCI is overkill. My built in 1983 house has NO AFCI breakers - and I intend to keep it that way.


----------



## Rich

scooper said:


> I think requiring every breaker to be AFCI or GFCI is overkill. My built in 1983 house has NO AFCI breakers - and I intend to keep it that way.


When we bought the house we live in almost 30 years ago, I replaced every receptacle in the place. If any of them fail, I will replace them with GFCIs, I'm a believer in them. My kitchen and TV room and both bathrooms have GFCI protection and they are not problematic. If you replace the first receptacle on a circuit with a GFCI, all the receptacles and switches downstream of the GFCI will be protected by that one GFCI.

Rich


----------



## inkahauts

Well afci breakers are a whole other ball of wax. 

And I'm for gfi plugs where you have water. Kitchens bathrooms and outside. But in a living room for tvs and bedrooms no thanks. I can't think of a positive reason for them.

Why do you find them necessary there?

And if you hook them up like you suggest in series you are screwed if one dies and all your power is always draining on it on that circuit. I wire plugs in parallel always myself if they re not a gfi circuit.


----------



## SayWhat?

Rich said:


> When we bought the house we live in almost 30 years ago, I replaced every receptacle in the place. If any of them fail, I will replace them with GFCIs, I'm a believer in them. My kitchen and TV room and both bathrooms have GFCI protection and they are not problematic. If you replace the first receptacle on a circuit with a GFCI, all the receptacles and switches downstream of the GFCI will be protected by that one GFCI.
> 
> Rich


You're asking for headaches. GFCIs age (go End Of Life) and will fail for no reason at all. If that happens they cannot be reset and must be replaced. I've had it happen several times in recent years. I only use them in potentially wet areas.


----------



## inkahauts

SayWhat? said:


> You're asking for headaches. GFCIs age (go End Of Life) and will fail for no reason at all. If that happens they cannot be reset and must be replaced. I've had it happen several times in recent years. I only use them in potentially wet areas.


I have had to replace way to many (especially at one friends house) because they just get old and their ability to handle normal fluctuations becomes flaky at best. Fluctuations like power draw of turning a hair dryer on and off. Id never want to trust one on my home theater system.


----------



## TXD16

inkahauts said:


> I have had to replace way to many (especially at one friends house) because they just get old and their ability to handle normal fluctuations becomes flaky at best. Fluctuations like power draw of turning a hair dryer on and off. Id never want to trust one on my home theater system.


About every tenth or so time we turn off the ceiling fan in the master bedroom, the GFCI breaker on that circuit trips, shutting down all bedroom electronics and requiring a frustrating trek to the breaker box. On the other hand, nothing that has ever happened in the master bath, which is immediately adjacent to the MB but on a completely separate circuit, has ever tripped either the outlet-protected GFCIs nor the breaker controlling the same. I've replaced both the fan and the switch, to no avail, and am now going to simply replace the breaker with a non-GFCI one. There's simply no reason for it in this particular installation.


----------



## Herdfan

TXD16 said:


> About every tenth or so time we turn off the ceiling fan in the master bedroom, the GFCI breaker on that circuit trips, shutting down all bedroom electronics and requiring a frustrating trek to the breaker box.


That sounds more like an AFCI breaker. How old is the house?


----------



## Cholly

I hadn't been aware of AFCI's until yesterday. I did a Google search on AFCI and came up with a Wikipedia link that discusses them. Was surpised to see that the electrical code mandates them almost everywhere in residences. :eek2:

https://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter


----------



## P Smith

Don't miss the phrase at a picture:
"This AFCI (the circuit breaker with the yellow label) is an older generation AFCI circuit breaker. The current (as of 2013) devices are referred to as "combination type" and usually appear with a green label."


----------



## TXD16

Herdfan said:


> That sounds more like an AFCI breaker. How old is the house?


Until your comment, I had never looked particularly closely at the breaker itself, but you are correct, it is, indeed, an AFCI (yellow label). Now, it's definitely getting replaced.


----------

