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NEC ground wire connections

raynb3's picture

What does the NEC say about how ground wires should be connected to each other in a box?  I read Rex Cauldwell's How to Wire a House; if I recall correctly, he prefers wire nuts because future changes are easier to accomodate.  Have also heard that inspectors sometimes insist on crimping (with the hollow brass crimp).

A second semi-related "settle a bet" question:  Should solid strand wires be twisted before wire-nutting?  (I say yes)

Thanks to all  electrical wizards who keep me from endangering myself.

(post #93868, reply #1 of 13)

As long as it's a listed connector or as the NEC says in 110.14 "identified" either way is alright. I like the copper crimps (bucannan) because they take up less room. But you need to use the correct 4 way crimping tool, which is a little pricey.

I always twist all wires before wire nuts or crimping so you have a good mechanical and electrical connection, but some don't, it's a matter of choice not code.

(post #93868, reply #6 of 13)


Hey pard, what's your basis for saying that the copper sleeves have to be crimped using the Buchannan C-24 tool (the one that does the cool 4-way crimp)?

If you're using the C-24 system--the crimp sleeve and the snap-on insulator cap--then you have to use the C-24 crimper. It's a great system, solid as a rock, and a pain in the butt if you ever have to break a splice. It's great for stranded wire. Mainly I use the C-24 system (sleeve + insulator cap + C-24 tool) for all conductors in life-critical circuits.

But for splicing grounds, I use Buchannan copper sleeves and a regular crimper made for non-insulated terminals. Usually, I use my sidecuts (lineman's), which have a crimp die at the back of the hinge (see page 80, issue 144 - January 2002). If space is tight, I use a crimper plier. Klein makes a real nice one with a cutter at the tip of the nose, and two die pockets for non-insulated terminals--and you need the larger one when using the bigger sleeves.

Take my advice--don't use the steel sleeves. Thay don't offer any advangtage, are harder to crimp on, and real tough to remove.

As far as using wire nuts for splicing the grounds, the AHJs here insist that a crimp sleeve be used. The way the sleeve is listed, you have to twist the wires.

Can't say that using a crimped-on sleeve a bad idea, seeing as how the consequences of an open ground could be serious (and you won't know there's an open till there's a problem).

As far as it being easier to break a splice made with a wirenut, it's very rare you have to open a grounds splice. Only for adding on to the circuit; I've almost never opened a ground splice for troubleshooting. If you do have to break the splice, it's not hard to cut the copper sleeve off with dikes (cutting along the length of the wires, then peeling the sleeve back). Harder than a wirenut, sure. Worth the extra security? I think so.

Adios amigo,

Marshall Dillon (aka CAP)

(post #93868, reply #7 of 13)

Well CAP, You're right as usual. I was thinking about the crimps as  used with the insulated caps. I've done like you and used my kleins many times for grounding conductors. The thing is I wanted to put it out there that there is a crimping tool, basically because I find it to be a much better connection.

I see the crimps and caps everywhere for sale but never the tool. So.... I guess I should have been clearer. Just trying to inform not demand! 

Keep up the good work on the articles. Peace!

Well, I thought of something else. You said your AHJ requires a barrel crimp. Awhile back I think it was Brownbag who said his wanted the green wire nut. Now I know every place has it's exceptions to the NEC but can the AHJ demand anything if it isn't in the codebook? Whatever codebook that might be?

I know it's easier to get along with Mr. inspector, but I've heard other's say to make an inspector show the code reference when they make a demand such as this , kinda like you called me out on the crimpers ha! ha!  

Edited 11/7/2003 1:51:31 PM ET by festus

(post #93868, reply #8 of 13)


You make a good point (& brownbagg before you) that you've always got the right to ask the inspector for a Code reference.

In this case, requiring the crimp sleeves instead of wirenuts, my local inspectors don't have a leg to stand on. There are some local Code amendments, but method of EGC splicing ain't one of 'em. I'm not gonna fight a battle over it, but I'm used to using the crimp barrels, and I think it's a better way than wire nuts. And everyone here has to use the barrels (which take a bit more time than a wirenut), so it's a level playing field.

Hey, I didn't mean to bust your chops on the crimper thing! I was asking you about it, wondering if I was doing it wrong!

Thanks for the encouragement on the articles. Got a couple in the works.

About the C-24 tools, check out e-bay. I bought a couple of pairs new (but with shop-worn packaging) for cheap. Not suprising--not many people use them anymore (some fed govt contracts used to require it, don't know about now). But I guess it's different in your area.



(post #93868, reply #10 of 13)

Just to note that Browbag's inspector required a lot of strange things. A few against the NEC.

If I remember correctly, but I might not, one of the things was prohibiting the use of 2 ground rods.

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #93868, reply #12 of 13)

Bill & CAP,

Thanks for the replys, Like everybody else I try to learn a little something new everyday.

 Bill I agree, Brownbag's inspector seemed to have his own codebook.

 CAP I've seen you get hammered a little on some of the electrical sites, thought maybe you wanted some payback! LOL!

There's so much  information on the internet it's hard to know what to believe, I never knew about all the required listing, UL white pages and code exceptions until I found the Web.

It's hard to discuss electrical work without hitting the regional wall.

 Cap, i'll keep the dust off my crimpers ( bought mine on e-bay too) and you keep your torque screwdriver polished, and we'll both be happy!


Edited 11/7/2003 5:15:02 PM ET by festus

(post #93868, reply #2 of 13)

I have no idea if it's code or not, and I'm certainly not a pro electrician.

But it seems to me it's a good idea to twist them. It's hard to hold them all the ends even when you put the wire nut on.

I spent a lot of time once chasing down a dead circuit. Turns out one of the wires had slipped out of the wire nut in a switch box. The electrician hadn't twisted the wires, and the wire simply fell out.

After that, I'll never put a set of wires together without twisting them.

We should all help stamp out, eliminate abolish, and otherwise avoid redundancy.

(post #93868, reply #3 of 13)

I think you will find that those crimp sleeves are steel, not copper.  The green pass-through wire nuts are great but can be a problem if getting close to wire fill limits.  I have been told that the crimp with a tongue is acceptable (-.  The type that you use with solderless connectors is not acceptable. 

For those who have fought for it Freedom has a flavor the protected will never know.

(post #93868, reply #4 of 13)

You can get the crimps in either steel or copper. On romex. I use the crimp with a  tongue long enough to meet NEC requirements for the amount of wire to free when pulled out of the box..6". You can the attach it to any device or multiple devices.

I always twist solid copper wire before wire nutting. Stranded wire, I let the wire nut twist them for me, it does a neater and better job. For stranded to solid conections I agian let the wire nut do the twisting. On larger bundles of stranded and solid , if it doesn't feel right on the tug test, I'll take it all apart and solder the joint b/f wire nutting. Every wire nut is twisted down with my linemans pliers. Fingers can't get them that tight. Every joint is tug tested b/f being pushed back in the box. No exposed conductors outside of the wire nut  is also a rule. Any reservations about the wire nut means it also gets taped to reduce the possibility of it backing off.

99% of my electric work is in metal boxes and conduite. A wire coming loose in a metal box is a lot more "enlightening" than in most type nm boxes.


(post #93868, reply #9 of 13)

"99% of my electric work is in metal boxes and conduite. A wire coming loose in a metal box is a lot more "enlightening" than in most type nm boxes."

Since it is a metal box wounldn't "endarkening" be a better discription <G>.

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #93868, reply #11 of 13)

Do you have to use a green wirenut on the ground wires (if you wirenut the connections), or can you use any color that will fit appropriately?

Thanks,   vlperk

(post #93868, reply #5 of 13)

Do you have to twist them together? No. If you read the box that 3M wirenuts come in, the manufacturer says that it's unneccessary.I don't.If anything you run the risk of breaking a conductor off by over torqueing them.

(post #93868, reply #13 of 13)

FWIW I never liked those crimps. Have done a few where required. No sense aggravating the AHJ over a minor issue. NEC and many local codes just asks for an approved connector be used in an approved manner. That said the NEC clearly bows to the AHJ as the final authority. So arguing that the NEC doesn't demand a crimp isn't going to change any minds unless they were leaning that way anyway. Some inspectors are easier to talk to than others.

My gripes with crimps:

They seem less easy to check visually. Give only a limited exposure I have seen, far too great a percentage for my comfort but this could be the result of a few maladroit electricians, a remarkable number of crimp connections that looked good but either did not provide a good electrical connection or at least one of the conductors was loose enough slip out easily.

I suspect that either the wrong tool was used, the crimp loosened over time with heat cycling or, as stated above, the electrician was sloppy. Short of watching each connection being made how does one assure the right tool is used. Wirenuts use fingers. Good assumption that most electricians have that tool.

Crimps are solid when properly made. Maybe too solid. Difficulty rewiring is only the start. Adding a cable to a shortwired box with a crimp gripping the last half inch of the one inch available is quite aggravating. As noted: Even more so if the crimp is plated steel. This can be worked with a bit of time and talent. It's only money.

My concern is that with variable loading induced heat cycling the crimp connection seems to, at least sometimes, loosen. Most wirenuts use a spiral spring that is designed to expand and contract with the connection. I'm not so sure of the crimps.