Ok, so here's an easy question.
I'm installing the outlets in my new house. I know that the code does not specify the orientation of the ground slot (up or down), however, Ray Mullen's residential wiring guide suggests the ground in the up position is superior. His reasoning is that if you have a metal cover plate and it comes loose, kit will hit the ground and not a hot prong. Yet, every house I look at has the outlets installed with the ground slot on the bottom.
Opinions?
Glen
Glenn
After a hard whooping from the moderators of this great site I have been ask to return to this site and do some educating.
First we must determine just what you are talking about when you refer to an outlet.
The term outlet as defined in Article 100 of the NEC is a point on the wiring system where current is taken to supply utilization equipment.
The two most common outlets that should come to mind are lighting outlets and receptacle outlets. I am sure that Ray Mullin and Rex Cauldwell both authors of some of the best electrical training books on the market will point out what an outlet is in their respective text.
Now some might say, what is the difference? The major difference is that you as someone trying to learn something about receptacles know that there is a difference in a receptacle and an outlet. Receptacle outlets are defined in the NEC as follows:
Receptacle Outlet. An outlet where one or more receptacles are installed.
When it comes to the orientation of the grounding pin of a receptacle it can be argued either way. I look at what is likely to happen and what has been documented in the past.
We hear stories every day but most of the stories we hear are just that, stories.
Ray as well as several others will debate that in the event of a metal plate coming lose it would be better for the plate to land on the grounding pin of a cord cap should one be installed. I always ask just how many cover plates have come off the devices in your home. How many have you ever seen just hanging on a cord cap?
This is a very unlikely event and should not be brought into the discussion unless there are documented cases of where this is a problem. If it should become a problem then UL would address the 6/32 by ½ screw that holds the plate cover in place.
Just as many will debate that the ground pin of a receptacle should be installed looking downward. Their reasoning is that a right angle cord will plug in with out bending the cord back over itself. This could cause the insulation on the cord to crack and start arcing across the conductors which will result in a fire.
This break down of the insulation on cords was the forerunner for the induction of arc-fault protection on bedroom circuits in the NEC. The first arc-fault devices were designed to detect parallel arcs such as would occur in the event of cracking of the insulation of the cord that was folded back across itself starts arcing from one conductor to the other.
There is no code rule that mandates the orientation of the grounding pin of a receptacle. In the event that the appliance being used caused the cord to fold back across itself it would be a good idea to reverse the receptacle to relieve the strain on the cord no matter which way it was originally installed.
Remember that a receptacle outlet (the box) will be turned so that it can be installed on the stud but the receptacle can be installed as the installer desires. The correct orientation of the ground pin is at the discretion of the installer and anything else is nothing more than opinion. I am sure that you have heard the old saying about opinions and everybody have one just as everyone having something else and both probably stink.
It is also important to know terminology when talking about trades. Some will sit back and laugh at my determination between an outlet and a receptacle.
There are many plumbing moderators on this site and I wonder how they would respond should I ask if I can install a tee in a waste water drain. Can this question be answered with a simple yes or no? Will you want more information so we can reference Table 706.3 of the code? (Notice that I didn’t say anything about a sanitary tee)
The same is true for electrical.
For the plumbing moderators which way does the ground pin go on an outlet?
Bottom line is if you are going to walk the walk then learn how to talk the talk.