Receptacle wiring

[Jim Robinson]

I'm working on my addition, and I'm helping the electrician of record to save some money. He wants me to wire the receptacles with a wire nut on the line and load wires and a third wire connected (pig-tailed) to the device. I have no problem with this, nor did I have a problem with the traditional method of wiring line and load to the terminal screws.

My question is: Is this required by NEC, or just a good practice for wiring receptacles?

[Tony Mount]

Jim, I was always taught that pigtailed circuits were always better because it does not relie on a mechanical device to complete the circuit. Usually there is not enough room in plug boxes to make up circuits and install outlets so be careful.

[Roland Miller]

If it is a multi-wire branch circuit--pigtailing the neutral is required. This prevents the possibility of applying a higher then normal voltage to appliances if the receptacle is ever removed for replacement.

The hot side is optional as is the equipment grounding conductor. Although there is no way to terminate the equipment grounding conductor without pigtailing ( more the one).

So the bottom line is you might as well do it all. IMHO-- it is a labor savor when installing the devices.

[Gunnar Alquist]

Jim,

The standard receptacle outlet is only rated for 15 amps. If this is a 20 amp circuit, the pig-tailed method is required. As Tony said, this prevents the outlet from completing the circuit. This also can save stress on the conductors as the pig-tailed wires will be the only ones to be pulled out of the box.

[Roland Miller]

Jim,

The standard receptacle outlet is only rated for 15 amps. If this is a 20 amp circuit, the pig-tailed method is required. As Tony said, this prevents the outlet from completing the circuit. This also can save stress on the conductors as the pig-tailed wires will be the only ones to be pulled out of the box.

Where are you finding your information?? The only NEC requirement is for a multi-wire branch circuit.

Thanks

[Jim Robinson]

As I said, I have no problem with the method. It does prevent a loose wire at the receptacle from killing to entire circuit down stream. I was just curious if it was required. No 12-3 circuits in this application. It's strictly 12-2 wiring with 20 amp breakers.

Thanks for the feedback. Now, if I could get my plumber to show up on the days that I need him to I'd be rocking this project.

[Jerry Peck]

Jim,

If the circuit is a multiwire circuit, then the grounded conductor is required to be connected in such a way that removing the device (the receptacle in this case) does not break the continuity of the grounded conductor.

There are two reasons, one Rolland explained: If the neutral is broken, the grounded center point between the two legs of the multiwire circuit are now free to float based on the current through them and the resistance/inductance of the loads, causing the voltages to skew from 120 volts. It would not take much to put 180 volts on one leg and 40 volts on the other leg, neither being good for whatever is connected to the circuit.

The other is that there may be current flowing through that neutral conductor and breaking the neutral circuit could lead to an arc, shock, and other hazards.

If your electrician has a policy of always installing devices that way, you found a "keeper", keep him and learn from him, and use him as a reference for when you need information.

That is an excellent policy to follow, and, if the box is too small, install a deeper box which will allow for that practice, don't let a too-small-box-size limit a good practice.

[Jim Port]

Jim,

The standard receptacle outlet is only rated for 15 amps. If this is a 20 amp circuit, the pig-tailed method is required. As Tony said, this prevents the outlet from completing the circuit. This also can save stress on the conductors as the pig-tailed wires will be the only ones to be pulled out of the box.

The slots only accept 15 amp device plugs. The device itself is rated for 20 amp pass-thru.

The pigtailing is not required on 15 or 20 amp circuits, except as has already been explained about the neutrals.

On a side not the 08 NEC has added a requirement that all multi-wire branch circuits has a simultaneous disconnect for both hot conductors and that the conductors be grouped. Prior to this it was only required if both circuits landed on the same device strap.

[Gunnar Alquist]

Where are you finding your information?? The only NEC requirement is for a multi-wire branch circuit.

Thanks

Roland,

I will have to do some searching. I will get back to you.

[Shannon Guinn]

Hopefully MWBC (in residential at least) will go the way of the dodo bird.;)

[Ken Lyons]

I personally like Multi-Wire circuits, they are standard in commerical and I have it in my own house. Saves copper, provided you do it right. I use a double-ganged breaker for each major room in the house. Which covers disconnecting both hots at the same place. I hate daisy chaining but if I have to I use the pig tail method.

Three conductors plus ground (one 12-3) versus four conductors plus two ground (two 12-2 romex). It saves redunant ground wires.

I can't count the number of houses I've seen where half the house is on ONE circuit 12-2.

Europe uses the junction box method above the outlet..a covered plate near the top of the wall above each outlet and light switch. The line runs all the way around a room at the top and each box branches off to an outlet below.. You always know where the wires are in the wall. I won't even mention 3 phase residential over there.


Ken

[Jerry Peck]

It saves redunant ground wires.

And there is something wrong with having "redunant ground wires"?

Redundancy adds another layer or protection.

I'm with Shannon "Hopefully MWBC (in residential at least) will go the way of the dodo bird."

[Ken Lyons]

Must be the commercial side in me.
Lots of copper = costs more in labor, materials and neatness.

Typical large house: 30 circuits (assuming all were 15/20 amp)
30*300' = 9000' of 12-2 Romex (*3=27,000' of wire)
30*3= 90 terminations in Panel

15*300 = 4500' of 12-3 Romex (*4=14,000' of wire)
15*4 = 60 terminations in Panel

It may go the way of the dodo, but I still like it...

[Jerry Peck]

Must be the commercial side in me.

It may go the way of the dodo, but I still like it...

In non-residential, I see no problem with multiwire circuits, it is residential we are talking about here on this board, and residential that Shannon was (I think) referring to.

In residential, non-qualified people work on their electrical systems, it is a fact of like, like blind people walking across traffic roadways - they need all the guidance they can get, and then walk only where that guidance leads them.

In non-residential, the people working on the electrical systems are "qualified" (or at least to a great extent "somewhat qualified").

[Gunnar Alquist]

I tend to agree with JP. I frequently find improperly wired multi-wired circuits. Found one yesterday. It seem like too many people purchase the "wiring simplified" book from the big orange box and think they understand wiring. Not sure if MW circuits are not covered, or if they only read part of the first chapter.

On a related note, did anyone see the recent CPSC recall of a home wiring book because it could lead to electrocution? Must have had some bad information in it. :rolleyes:

[Jerry Peck]

Gunnar,

It's because they go to the Big Box stores and are told "All you need to remember is *white goes to white* and *black goes to black* ... " :rolleyes:

[Ken Lyons]

Faulty Instructions Prompt Recall of Electrical Wiring How-to-Books by The Taunton Press; Shock Hazard to Consumers (http://www.cpsc.gov/cpscpub/prerel/prhtml09/09078.html)

Hazard: The books contain several errors in the technical diagrams that could lead consumers to incorrectly install or repair electrical wiring, posing an electrical shock hazard to consumers.

Hum...Hot to Ground or they skipped grounding completely?
Or better yet, put the switch on the neutral side...I love those.