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View Full Version : Another Electric Wiring Question: Chaining Outlets



Paul Alciatore
10-23-2014, 03:02 PM
I am posting this in a new thread to avoid hijacking the other one. In that other thread about grounding and ground fault protection, J Tiers said,


For the US, it was common in the past (not accepted now) to wire from outlet to outlet by connecting incoming wires to one line/neutral pair of the screws on an outlet, and wiring off the second pair to go to more outlets on the circuit. If the incoming wires ...

I am not an electrician and was not aware that running from one outlet to the next was not an acceptable practice. I have never been a fan of using those "poke the wire in" holes for any wiring, but I fail to see any problem with using the screw terminals to chain the circuit to the next outlet. And virtually every 115V, 15/20 Amp. outlet in every electric supply house and hardware store and home supply store in the country has the double screws with a break off link between them. I would think that if they were no longer used, the manufacturers would save a few pennies by eliminating the second screws. I mean two screws per outlet and less metal under them; that's gotta be at least $0.01 or $0.02 per outlet. Millions and millions of dollars in a year.

Is this the case or am I misunderstanding? Is this just a problem with a GFI circuit? Or has it been banned for all new wiring?

AND WHY?

millhand
10-23-2014, 03:30 PM
The National Electrical Code specifies that receptacles be wired so that removing one outlet does not interrupt the supply to outlets farther down the line. This in effect requires that the receptacle not be used as a splicing device. So the proper installation of receptacles is to splice the incoming and outgoing wires to a pigtail that only connects to the outlet in the box. If there are two recepts, two pigtails are required. In addition, connecting the circuit through the recept effectively uses it as a splicing device and they are not UL listed for this purpose.
Carl

winchman
10-23-2014, 03:35 PM
I've never chained outlets using the screws or the push-ins. I always used a wire nut to join the incoming and outgoing leads with pigtails running to the outlet. It passed inspection, so it must have been correct. :D

The only time I've broken off the joiner between the screw tabs was to use one part of the outlet for a switched receptacle on the same circuit.

RichR
10-23-2014, 03:54 PM
For the US, it was common in the past (not accepted now) to wire from outlet to outlet by connecting incoming wires to one line/neutral pair of the screws on an outlet, and wiring off the second pair to go to more outlets on the circuit. If the incoming wires ...
Does this apply to GFI outlets if you want to use one to protect outlets downstream?

Gary Paine
10-23-2014, 04:24 PM
To pass the inspector's review when I built my shop, I had to use a copper crimp ring on the ground wires in each box when running the circuits.

Bob Ford
10-23-2014, 05:43 PM
The old way of using the screws to make connections for the circuit. Had one big drawback. If you were replacing a receptacle hot when you broke the neutral you could easily make connection between the neutral coming from the panel and the neutral coming from the load. The voltage going from one hand up your arm through your heart then down the other arm and hand and on to the panel. 110-120 at 60 cycles is one of the best to stop your heart. Simply put there was getting to be too many dead bodies, so change in rules. The main reason for codes is to stop fires and keep people alive.

Bob

justanengineer
10-23-2014, 06:44 PM
Is this the case or am I misunderstanding? Is this just a problem with a GFI circuit? Or has it been banned for all new wiring?


JTiers is wrong if he's talking about 110V circuits, but this is a common misconception as we're already seeing. Folks dont understand the definition of the NEC's term "multi-wire branch circuit" which by definition cannot be a 110V circuit, "multiwire" means more than one hot conductor. The reason you do not chain 220 or 440 devices is obvious, so you dont accidentally end up with the wrong voltage going through the wrong device causing a fire.

Youre talking 110V, so youre fine to wire from outlet to outlet. Its still a popular method of new construction.

Joe_B
10-23-2014, 06:59 PM
My house was built in the fifties and is wired with the outlets chained. It is a huge pain in the ass when you want to replace an outlet. You never know what else you are going to kill when you disconnect one. If I was wiring something up, I would never chain outlets.

J Tiers
10-23-2014, 07:49 PM
JTiers is wrong if he's talking about 110V circuits, but this is a common misconception as we're already seeing.

It's definitely NG for a multiwire, and it is rotten bad practice for a single branch. Quite a few local inspectors do make the extension from multiwire to single circuit, not allowing the chaining for that either.

I have no clue why anyone would do it, it's not much less trouble to chain vs pigtail, and a LOT more trouble to replace. I have it all over my place from 80 years ago, and I do not like it at all.

The equipment grounding conductor should NOT be chained.

lakeside53
10-23-2014, 08:09 PM
Receptacles only have provision for one ground wire so chaining isn't an option.

If you don't want "replace" receptacles because of wear, just use spec grade. These come in a few forms, but most today have a clamp bar for 4 wires on each side. Chaining with these is fine and a common practice around here. Yes, I see the argument for pigtails but it's far easier and quite safe to use this on the aforementioned types, especially for "quad and hex-plex" arrangements on one box.

The push in wire types should be banned -junk; I had a house full of them once..

Edwin Dirnbeck
10-23-2014, 08:20 PM
The old way of using the screws to make connections for the circuit. Had one big drawback. If you were replacing a receptacle hot when you broke the neutral you could easily make connection between the neutral coming from the panel and the neutral coming from the load. The voltage going from one hand up your arm through your heart then down the other arm and hand and on to the panel. 110-120 at 60 cycles is one of the best to stop your heart. Simply put there was getting to be too many dead bodies, so change in rules. The main reason for codes is to stop fires and keep people alive.

Bob

I can see that pigtails would be safer but isnt it also forbiden to replace a hot receptacle.I seem to remember a thread that stated in a factory setting ,anyone working on a live wire would be instantly terminated. Edwin

tlfamm
10-23-2014, 09:16 PM
I was taught 40 years ago by an electrician to always feed devices (outlets, switches, light fixtures) with pigtails - and the pigtails are attached to the screw-terminals, not to the push-in connections. I've seen two of the latter fail in my daughter's condo.

As for multiple devices in the same box, I can't really remember if we pigtailed each or not. In my own home I think I have jumpered from one set of device terminals to those of another device (including ground).




Edit: make the post a bit more clear

J Tiers
10-23-2014, 09:30 PM
I see nothing wrong with a pigtail to one duplex, and chain to the others IN ONE BOX. I don't like it for 'circuits" because of the chance for wire damage when replacing outlets. Also a decent chance of some dufus reversing the wires and putting hot on the neutral for all downstream devices, lampholders, etc. (Can't happen? You have not seen what I have seen....)

You don't damage the through wires if you have pigtails, no reason to disturb them at all, just the pigtail end, and that can be cut back and re-stripped if it is ever needed.

As for spec-grade, I would only put them in, not the consumer junk. But they are not easily available with internal blocking shields for use in houses having kids. Only the lower grades are easily gotten with that feature, which may be required in some areas.


I can see that pigtails would be safer but isnt it also forbiden to replace a hot receptacle.I seem to remember a thread that stated in a factory setting ,anyone working on a live wire would be instantly terminated. Edwin

It's stupid to do it if you can do the job without it. Sometimes you cannot. As with replacing a meter box, most electricians would do that hot.

Any factory has it's own rules. I'd fire someone for doing it if there was any reasonable way to kill the circuit. And there pretty much always is, aside from red-faced screaming managers.....

justanengineer
10-23-2014, 10:03 PM
I have no clue why anyone would do it, it's not much less trouble to chain vs pigtail, and a LOT more trouble to replace. I have it all over my place from 80 years ago, and I do not like it at all.


1. Bc its vastly easier to install and repair in buildings with plaster or where you otherwise dont want to cut the wall or ceiling. No need to dink around running/fastening unnecessary lengths of wire vertically through walls which is a royal PITA unless you cut the wall. I did every room in my house without cutting the plaster, each room taking about an hour to replace 4-6 outlets, a light + switch, and 2 basic loops of wire instead of a spider-web lookin mess. I'd hate to think of how many holes Id have to punch in the wall just to staple the dam things if I was pigtailing to local code.
2. Bc its vastly cheaper. Pigtailing means you need to install extra, oversize boxes (time + $$$ - potentially for every outlet) plus extra wire, wire nuts, etc. Chaining eliminates the extra boxes and extra issues.

Bob Ford
10-23-2014, 11:22 PM
First I spent 35 years as a union construction Electrician. First five as a apprentice. Taught journeyman classes for about fifteen years.

Some times it is near impossible to find where a receptacle is fed from. Daryl and his other brother Daryl do some very interesting wiring. I remember one old store had six sub panels A through F. I needed to change a receptacle that was in the area fed by A panel. Went to panel A and found circuit directory clearly mark for Room I was working on turned off breaker, receptacle was still hot. Turned off all of panel A receptacle was still hot. Turned A back on Pulled main breaker for panel B receptacle was still hot. Turned B on and pulled main on C. Receptacle still hot. Turn C back on and pulled main on D. Receptacle still hot. Turned D on and pulled main for E. Receptacle still hot. Turned E back on and pulled main for F. Receptacle still hot. Decided it would be easier to change hot. When I removed the first wire from the hot side it check out hot so capped it off and did a reading on the receptacle it was still hot. Went to panel A and pulled main. Capped wire was dead receptacle was still live. Went through shutting one panel at a time and found the receptacle was also fed from panel E. Daryl and his brother were lucky enough to get both circuits on the same phase. I capped the wire from panel E labeled it and put it back in the box put a new receptacle on the wires from panel A. The people were a little pissed to get a bill for three hours to do a fifteen minute job. Working on old wiring where the expert electricians are shoe salesmen during the day you find very interesting ways that the work was done. Some times it was safe. Lot of times it was a wonder there was no fire.

Bob

J Tiers
10-23-2014, 11:41 PM
1. Bc its vastly easier to install and repair in buildings with plaster or where you otherwise dont want to cut the wall or ceiling. No need to dink around running/fastening unnecessary lengths of wire vertically through walls which is a royal PITA unless you cut the wall. I did every room in my house without cutting the plaster, each room taking about an hour to replace 4-6 outlets, a light + switch, and 2 basic loops of wire instead of a spider-web lookin mess. I'd hate to think of how many holes Id have to punch in the wall just to staple the dam things if I was pigtailing to local code.
2. Bc its vastly cheaper. Pigtailing means you need to install extra, oversize boxes (time + $$$ - potentially for every outlet) plus extra wire, wire nuts, etc. Chaining eliminates the extra boxes and extra issues.

it's not really any cheaper....Definitely not "vastly" cheaper.... The amount of extra wire is trivial. Wire nuts are cheap. You take the same two hot and neutral wires you would have anyway, you add one wire nut per wire, and another 6" of wire. You need to connect only ONE set to the outlet, the through wires and wire nuts go to the back of the box, and you 'dink around" tightening screws only 2 times (plus ground) instead of 4 per box. You are already doing it for the ground wire.

As for easier to install, that makes absolutely NO SENSE... I do NOT think you have any concept of what "pigtailing" involves, which is nearly nothing extra. Maybe you think it is something akin to a "fixture whip". No, it is not like that.

The same two cables come to the same box, running the same way in the wall. I have NO idea where you are getting the deal about punching extra holes, etc..... That would form absolutely NO PART of what we mentioned here.

VASTLY easier to repair if NOT pigtailed? Please, do not make me laugh so hard again..... if anything it is "vastly" easier to repair if it IS pigtailed.

Dude.... the pigtails are two wires all in the same box with the outlet.... instead of the entering and leaving hot wire, for instance, going to the two screws on the hot side of the outlet, you wire-nut a 6" or so piece with them and that 6" piece connects to the hot on the outlet. DONE....

To remove and replace the outlet, you undo those two (hot and neutral), plus ground, and connect to the new outlet.... DONE. no fighting 5 wires in a little box.... the join goes in the back of the box, and just the three short wires come to the front.

Paul Alciatore
10-24-2014, 12:11 AM
Thanks for the explanation. To summarize what I understand from this:

1. Using the 115V, 15/20 Amp outlets for chaining is OK, but not best practice.

2. Connecting the wires in the back of the box and adding pigtails for the outlet is better and safer.

3. Cost for each way is about the same, only slightly more for pigtails.