here is one i have been wondering about & have no idea.why do outlets not have two green screws for the bare grounding wire? i know this sounds crazy but this has had me puzzled all day.they have two screws for the neutral & hot , bu not ground.

I have a few Sierra outlets that have the twin ground screws, but I'm guessing the idea of mounting a bare ground wire on the same side as the hot could lead to some interesting experiences if you're not careful...

Could also be something to do with current listing requirements

I would assume it is so you are not depepnding on the device as the fault clearing path. If you were to take out the device, you would have no path for fault current until you connected the two EGCs together. Sort of the same concept as 300.13(B) for the grounded conductor of multiwire circuits.

Frankly, I wish they only had one connection each for the hot & neutral also, making it impossible to depend on the device for circuit continuity.

Radar

2 hot and 2 neutral screws allows you to have a duplex receptacle with 2 separate circuits that don't share a neutral, using a 4-wire feed.

Ryan J has got it: 2 ground screws would allow for non-pigtailed grounds. If the receptacle was ever removed, the ground would be interrupted to devices "downstream".

I agree with Ryan and Sixer that having and using two ground screws on devices would lead to 250.148 violations.

250.148 in part


I can not agree with that.

You are free to pigtail the device if you want but assuming proper installation it is not unsafe to feed through a device.

Bob

It's amazing the assumptionf different folks make. These assumptions may never even be reflected in, or inferred to by, standards and codes....but they are there nonetheless.

Having dealt with some folks in the design and testing of receptacles....they, like most real electricians, assume that only a DIY will actually connect two set of wire to a device- surely not more than that! It is also recognised that it is a fairly common trade practice to "split" a receptacle. (Switched receptacles for lighting and the dishwasher/disposal receptacle are prime examples of this).

And, unless you're a HIY or tract hacker, you use a pigtail.

Another assumption these days is that you'll be using a "greenie" to join the grounds together.

Until recently, it was quite possible to legally wire a receptacle without connecting the ground wire directly to it; a connection to the metal box was considered sufficient. Even today, I think it is assumed that the primary connection will be to the box, with a eparate pigtail to the receptacle.

Receptacles probably would have been made completelt without a ground screw, except that, in plastic boxes, you really need to attach that wire to something! I'm certain this is the real reason switches have ground screws....speculation about metal cover plates notwithstanding!

"or tract hacker"...

Careful, you are talking about every 1&2 family electrician out there who wants to win a bid. Most I see "stab". Until U/L and NFPA say it is wrong, AHJs accept it.

Right, G, its' legal. At least, for up to two wires per side. More than that, and it's debatable.

But you assumption that the guys who do this might consider being called a "tract hacker" an insult may not be correct. These guys seem to take pride in just how fast, and cheaply, they can wire a house to the most minimum standard...I can even think of one member of this site who calls himself "Romex Racer." For all I know, 'track hack' might be the next rung of their professional ladder! :-)

When differentiating between two installation methods, both of which meet code, and both of which have been listed by a suitable testing lab, qualifying one as a 'hack' and the other as 'good workmanship' is at best a gut feeling supplemented by experience and anecdote.

'We all know that backstabs are bad.' Seems to me that well controlled spring tension in a device would do a better job of making a splice than a randomly tightened screw. At the same time I would never use a backstab.

Connecting two sets of wires to a device. When working with stranded wire and commercial 'back wire' receptacles, my _gut_ feeling is that the screw and pressure plate of the receptacle would make a better splice than a wire-nut. Barring multi-wire circuits, I will by preference connect multiple pairs of wires to such a receptacle.

-Jon

Everything also depends on the loads attached to the receptacle, in a house there will almost never be anything plugged in that would seriously strain a device, the obvious esceptions being airconditioners and space heaters. and if you work remodling houses you become very grateful for not having to jam a wirenut and extra wire into a box along with the old, stiff, rubber and cloth covered wire. Personally I think that the conection to the device is far, far more likely to fail then the device itself under load, especially if not properly installed.
I'd also like to say that back stabs may be a good thing for speed-freak tract home electricians, they do everything fast as possible, and if they had only screw terminals to hook to I can see such things as sticking unlooped wires under screws, not tightening screws down all the way etc.
-Will

renosteinke -

"Another assumption these days is that you'll be using a "greenie" to join the grounds together."

Ok, I'll show my ignorance, what is a "greenie" (and does it go by any other names)?

Steve

I found this, never seen one before https://www.electrical-contractor.net/forum/BUS/greenie.jpg

A "greenie" is a green wire nut, made by Ideal, that has a hole in the end. To use it, you trim all your grounds back (except one). You slip the long wire through the nut, out the hole, and several inches later, tighten the nut on the remaining grounds. This gives you a pigtail for attaching to a screw.

I prefer the buchannon or stak-on barrel crimps for ground connections. They use less space, and if installed properly make a good connection. Note the words installed properly.

They also make a greenie with an attached green insulated stranded 12ga pigtail that has a spade connector on it.
I am not sure how the money works out but they are great for retro work where the EGCs are too short to reach the device. I would think that would be good in those packed fan boxes on AFCIs too where an errant ground hitting the neutral can trip the AFCI.

Hello from South Dakota!!!!!

Forgive me for this, but I always thought that you had to pig-tail every device. I was always told that you could not rely on a device for circuit integrity, but then again I have never questioned that in 16 years.

Am I wrong?

Jon

Jon the NEC only requires the grounding conductor and the grounded conductor of a multiwire branch circuit to be pigtailed.

(Actually they do not require a pigtail but that is the result of what they do require)

Outside of those conductors you may use the device to feed through.

Pigtailing is one of the more common ways that "trade practice" exceeds code requirements.

[This message has been edited by renosteinke (edited 03-29-2006).]

Does it really exceed code requirements or is it simply acceptable?

Hello from South Dakota!!!!

Thanks iwire.
Now I feel stupid for not questioning that.

Does anyone think that it is a better or faster way of installing the devices by not tailing? How much time will I save in make up on the rough-in compared to time saved on the trim by hooking up just one wire per device? Or is it just a wash as far as time goes and we are just talking about the cost of wire nuts?

Jon

IMO pigtailing is just the right way to do the job!