? Stranded wire OK for grounding electrical boxes?

[zxcvbob]

It's really difficult to shove all the #12 solid wires back into a handybox when wiring a new 20A duplex outlet outlet and another cable exits the box to feed the next outlet. And the main problem seems to be the #12 wire to ground the box. I'm tempted to use #14 bare wire, since the box *should* be grounded by the yoke of the installed outlet. But even that would be a stiff solid wire going the wrong general direction to bend easily.

What about using #12 green-insulated stranded wire? Can it be twisted into the red wirenut with the other three #12 bare solid wires? Do I need to crimp on a terminal lug, or just twist the strands into a little loop and hook them under the green ground screw?

Even better would be to use a stranded wire pigtail on the outlet and a stranded wire for the box, so I'd have two solid grounding wire and two stranded wires.

I have one box to wire with *two* cables coming out of it feeded other boxes. That one will be really fun to get all the wires in. :-( I'll use an extra deep gangable box for that one and wire it up with the side removed until I shove wires in from the side.

I'm too stubborn to use plastic boxes for exposed work, but I am using plastic ceiling boxes just so I don't have to ground them.

Thanks, regards, Bob

[Jagoff Jameson]

What size box you got there space cadet? The cubic inches mandates the number of wires you can put in there. Give up and hire a pro.

[zxcvbob]

13 or 16.5 cu. in. for a handybox; I'm not sure if this is a 1 7/8" deep or 2 1/8" deep box (it looks like a deep box but the cubic inches is not stamped on it and I didn't measure it). In any case, the wires and the outlet require 13 cubic inches total, so it all fits in either size box but it's tight.

Why don't you go back to doing what you do best if you don't have anything useful to say, "Jagoff"?

Regards, Bob

[Chris Lewis]

According to zxcvbob :

I believe you're supposed to use terminal lugs for stranded wire used as house wire under simple screw terminators.

This is how I do this - fewer wirenuts.

Leave the ground wire on the feed cable _very_ long (like 8").

Run it direct to the closest box screw, half a turn, thence to the outlet ground screw (leave an inch or more of slack), thence to a wirenut to the ground of the downstream cable.

I do the same for the neutral (except for the box screw ;-)

[Toller]

Are you talking about running a #12 to the box grounding screw, and a #14 from the box to the outlet ground? Personally I wouldn't have a problem with that, but I think it would be a code violation unless you bought one of the more expensive outlets that has a self grounding screw hole in the yoke; then you don't need to run a wire to the outlet at all. (At least that is my understanding, which is not also infallible.)

I don't know of any code requirement on this, but it is a heck of a lot easier to crip a terminal on than to try to get stranded wire under a screw. Around here ground wires must be crimped together, not wirenutted. Crimping is much better than a wirenut if you are going to mix stranded and solid.

That seems fine, but I would crimp them. They sell a wirenut with a wire coming out of the opposite end with a lug on it. That would work nicely in this application, though as I said, they would be a code violation where I am.

I hope you never have to use #10. It is much worse than #12. (and so on...)

I use plastic everywhere except where I am concerned about something hitting it, but each to his own.

[Al]

Its people like you who really destroy diy.

[George E. Cawthon]

Hey, its even harder with #10, practically impossible. Everything I've read says you can use stranded wire pigtails and my electrical inspector even suggested it, but that was many years ago. I would use different colors of stranded wire. I think you could drop to #14 stranded wire to make it easier since the pigtails are only 2-3 inches, but don't know if that is code.

[zxcvbob]

Thanks. That helped tremendously. I just wired a box where I gave the ground supply wire 3/4 turn around a ground screw as soon as it entered the box and then wired the outlet as usual. The finished wires and device shoved into the box much easier.

I'm gonna use a deep plastic box (about 20 in3) for the one outlet box that will have three 12-2wg cables and a duplex receptacle all in one box, so I can eliminate the pesky equipment ground to the box altogether.

I saw some 8" flexible ground pigtails at the store yesterday. They were about 50 cents each so I didn't get any until I tried your trick first; they had a fork connector crimped on one end and a ring connector with and a captive ground screw on the other end of a green #12 stranded wire. I might get a couple for my junkbox because they could be really handy sometimes.

Best regards, Bob

[Chris Lewis]

I thought it might ;-)

I should also amplify a bit - our code (CEC - or at least our most common interpretation of it - the Knight "Orange" book) says that you're also supposed to bond together each metal box in a gang box install.

So, I run the bare wire straight from the feedclamp under one screw from _each_ box, then to the outlet, then wirenut to the outgoing feeds.

This means of course, you may well need more than a foot of bare wire off the end of the feed wire.

When I said "half a turn", I should have said "as much of a turn as you can do without overlapping".

The technique is recommended in Knight as meeting the pigtail rule (so the ground doesn't have to be disconnected to remove the outlet), eliminating a wirenut, and easier to stuff.

I do the same for neutrals (leaving out the box connect of course!). Ie: for the first connection, I put my wirestrippers where I need the loop, slide the insulation about an inch, repeating for each loop I need.

Neutrals require pigtailing for 240/120 4 wire circuits (eg: split duplex kitchen receptacles), but Knight recommends doing it with every outlet.

The technique is also useful with gang switches (feed to gang switch).

It's really cool when you can wire a 5-gang switch assembly with only

2 wirenuts. A wirenut for common ground, a wirenut for common neutral, and all the hots go to switch screws. No pigtailing of the hot.

I'm old-fashioned, and use deep metal boxes exclusively.

[zxcvbob]

Using a plastic box was kind of an extreme measure for me; I like metal boxes. But a 3 1/2" deep metal box wouldn't fit; the clamp screws would poke through the plywood sheathing. I found a plastic box that was about

2 3/4" deep and had 2 more cubic inches than a similar metal box. (This is an exterior wall of a detached garage with 2x4 studs, and I mounting the boxes so the fronts are flush with the face of the studs. If I ever finish the walls I'll have to move the boxes out, but that's OK because I mounted them with screws.)

Thanks again, Bob