Why pigtail inside a receptacle?

[rminv]

I'm connecting a new outlet to an old one. The old receptacle has holes in the back for backwiring and four screws on the side for sidewiring.

The guy at the hardware store said you could only hook one hot wire and one neutral to the receptacle. The other connections had to be pigtailed prior to connecting to the receptacle.

Seems like there are ample connection points with the backwire hole and side screws. If the hot wires are all connected to one side of the outlet and all the neutral to the sides, then why do I need to pigtail? Why can't I just use the outlet as a connection point (note the fin connecting top to bottom is still in place)? Seems like it would be functional electrically - is it just a code thing?

Thanks, Tim

[RBM]

Not knowing the wiring scheme in your outlet box, he may just be advising you of the safest way to wire it. In some cases there are two circuits brought into a junction box , sharing a neutral, for several runs of outlets, lights or whatever. When you have this situation, you cannot have the neutral conductors dependent upon a device, which is to say, they must be pigtailed. When you pigtail outlets, if one outlet fails, the others aren't affected.

[zxcvbob]

I think you can only hook one neutral wire to the outlet because you don't want the neutral of a downstream outlet be dependent on one another device -- if someone removes the outlet, all the others on the circuit now have an open neutral. The hot wire is not so important for safety, in my opinion, because all the downstream outlets will be dead if you remove the upstream outlet.

Also, the more wires you have attached to a device the harder it is to shove it into the box, even if the box is plenty big. Don't ask me how I know that.

Bob

[Toller]

If it is a code thing, it is just in your town. The rest of the country lets you chain them. Some people like pigtails because a defective outlet won't shut down the whole circuit. Or sometimes it is just easier to pigtail because the wires are too short to get to the outlet otherwise. He might be thinking of a switch; it is forbidden to take a connection off a switch, you must pigtail.

By the way, backstab connections are very bad; backclamp are okay.

[RBM]

It is a code thing, an NEC code thing. On multiwire branch circuit, (Edison circuit) Neutrals cannot be dependent upon a device

[rminv]

Can you explain why this is? I would have guessed that if someone removed the outlet they would reconnect the wires that were previously attached to it. If you had just pigtailed and disconnect the receptacle, the pigtailed end would still be hanging loose in a dangerous way.

[RBM]

It's not for that reason. IF, you have an Edison circuit, which is one where two hot legs of different potential, share a neutral, and you loose the continuity of the neutral, you get a 240 volt circuit between the two hot legs. Even momentarily this can cause havoc

[gfretwell]

If this is really multiwire at this point he will have worse problems than that. Without breaking the tab off he will have a bolted line/line fault

[Terry]

Which almost never happens in house wiring. To create this situation in a house you would have to go from recpt to recpt with 12/3 or 14/3.

The rare case where you do feed a recpt with a 3 conductor cable, only that box is required to have the neutral pigtailed.

As a rule, if the box only has black and white wires, you do not have a Edison circuit.

[RBM]

Why would he be inclined to put both hot legs on the outlet? If you opened up an outlet box with a multiwire circuit in the box, one leg would be on the outlet and the other leg would be under a wire nut feeding the other circuit

[RBM]

You're correct, it could only happen at a box where a mulit wire circuit exists, and only at that box, would you have to pigtail the neutrals

[Tim Smith]

And even if you, or people working with your permission, won't do dumb things, some future owner might, leaving a surprise for some farther-future owner. Best to do things right up front, to give future idiots less opportunity to screw up.

And never underestimate the kind of dumb things people might do. In my house, I had an outlet in the master bedroom that had open ground, as did the outlet in the master bathroom. The other outlets in the master bedroom that were on that circuit were fine. The electrician found the problem--the wiring went from the last good outlet up to the attic, to go over a door, and then down. Someone had cut the wires up there, and wired in a socket. (A single outlet socket, not the usual dual outlet socket. I didn't even know they made singles). Whoever did that had not bothered to hook the ground to the outlet--they just left the two ends of the cut ground line sitting there.

[Toller]

Oh sure, that must be the explanation. It must be a multiwire circuit on the outlet, and the clerk psychically knew that. Silly me for not thinking of that!

[Terry]

The clerk doesn't know what he is talking about. You don't need to pigtail the neutral except for the reasons RBM gave. Which is almost never in a house.

Pig-tailing the splices makes a better connection for more than one reason, but it is not required by the code.

Also, backstabs are cheaper and faster. That never equals better, but they sell them. They are legal.

[Justin West]

Code does make provisions for how many wires can go beneath a screw terminal. Most ignore the compression tabs provided on some receptacles.

[Czlowiek]

ok, then use braids.

[Chris Friesen]

This is standard wiring for kitchen counter receptacles in Canada. 15A splitwired, with top/bottom receptacles on different circuits.

Chris

[Noozer]

You can use the side screws to continue on two the next box, so that's two hot wires and two neutrals.

Don't even think of using those backstab holes. You'll regret it later.

[terry]

On May 13, 7:29 am, Chris Friesen wrote:

On May 13, 7:29 am, Chris Friesen wrote:

RBM had asked why put both legs on an outlet? I agree with Chris; this not uncommon AIUI here in Canada. Because instead the whole of say first duplex outlet being on Leg A and the whole next duplex outlet say on Leg B both the outlets have that little tag which is bridging the live/hot side of the upper and lower pins together removed and lower and upper (live side) are wired. The 'total' capacity of the circuit is that of the #12 wiring and its circuit breaker; 20 amps. Our house for example has a few outlets where these 'Split outlets' are used; effectively doubling the capacity of that outlet to 15 amps Leg A and 15 amps Leg 15 B. Our house has outlets wired with the then standard #12 AWG (115v circuit breakered at 20 amps) or in the case of these few 'split outlets', 115/115 3 wire #12AWG with 'double pole' 20 amp circuit breakers. We did not pigtail, daisy chaining the 12AWG through the outlets which here was/is OK to code. That meant in most cases four #12s per duplex box plus grounds. Apart from physical damage to a couple of 'bench outlets'; got to replace them, but they are completely 'off'' by a master switch when workshop unoccupied, no problems at all with outlet wiring in our 37 year old house. You have me thinking though about one situation where I picked up the live for a new switch for an added light socket at bottom of basement stairs. Probably all of one amp to a single 100 watt bulb! It is all safe and works fine; but! The switch box the added switch is wired comes from is congested. Already have a physically larger box standing by as a replacement to give more space; when I get around to it! But; did I pigtail that? Or come off the screw on the live side of that switch? Since this a lighting circuit using #14AWG, volume of wire inside lighting switch box not too hard to deal with. Thanks for the thoughts.

[Larry W]

Don't use the backstab holes to connect anything unless they are the type that clamps down onto the wire as the screws are tightened. The more common spring-loaded backstab connections often cause problems. If you connect to the additional outlet using the screws it will be OK, not sure what current code says about this.