Grounding Of Ground Wires In An Electrical Gang Box (how to handle the green ground wires)

[Robert11]

Hi,

I posted a question a while back regarding whether it was code permissible to ground the green wire grounds in a gang box by using a single screw that was also used to secure the box to a wooden joist. Responses were that it was not, and you must use a dedicated screw. Good information.

One reply also said that:

"The code also requires that a suitable connector must be used to splice the EGCs. just twisting them around each other is no enough. "

Questions:

a. What's an EGC ?

b. does this mean that if I have, e.g., two green ground wires in a box, I should twist them together with an Additional pigtail, put a screw twist-type connector over them, and then just run the new single pigtail to the ground screw ?

What's wrong with just twisting together the two green ground leads and running them together to the screw (perhaps adding a small flat washer over them if the buildup looks a bit large for the screw head) ? Adding an additional pigtail seems like a bit much.

Thoughts on ?

Thanks, B.

[Doug Miller]

Equipment Grounding Conductor, i.e. the bare (or green) wire.

That's correct.

Two problems:

First, "just twisting [them] together" is not a Code-approved method of joining them. An approved pressure connector (such as a wire nut) is

*required*.

Second, the Code also requires that terminals used with more than one conductor must be specifically approved for use with more than one conductor. "Adding a small flat washer over them" does not qualify.

Perhaps, but it is what the Code requires.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[HorneTD]

Grounding Conductor, Equipment. The conductor used to connect the non?current-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both, at the service equipment or at the source of a separately derived system.

You will need a second pig tail for the device if it needs one.

That is in fact what the US NEC requires. There is a listed pressure connector that has a hole in the tip for the longer EGC to be extended to the grounding screw. It is commonly called a greenie. A crimp sleeve can be used in the same way.

-- Tom H

[Eric Tonks]

A method I have seen used around here (Ontario, Canada) is to run the incoming ground wire under the box ground screw with a 4 to 6 inch length extending past the screw, then use a wire nut to attach all the other ground wires together. It keeps the wire bulk down to a minimum.

[The Real Tom]

IMHO:

Equipment Grounding Conductor. (the typically green or bare ground wire).

Sounds good to me!

Have to find it, but only one single wire loop under the screw is allowed.

This is why some people, strip back the wires and crimp them and cut them so only one long conductor is left, and that is put under the ground screw. There are 'greenies', wire nuts too.

hth,

tom @

[toller]

Around here they require grounds to be crimped together; wire nuts are not acceptable. Don't know why.

[Eric Tonks]

With the grounds crimped together, it would create a problem to change some of the newer electronic switches/timers/dimmers that need grounds. I find that todays equipment often fails or need changing to update automation controls. Cutting and crimping grounds could shorten the wires too much. Wire nuts seem a better method in my opinion.

[HorneTD]

That policy is often the result of a misapplication of 250.64 (C) which only applies to Grounding Electrode Conductors. Several jurisdictions have mistakenly applied this section to Equipment Grounding Conductors thus requiring crimp sleeves. Some of the larger electrical contracting firms have begun appealing this misapplication of the code because the crimp sleeves require a special tool and more time to apply thus raising the cost of the work needlessly.

250.64 Grounding Electrode Conductor Installation. Grounding electrode conductors shall be installed as specified in 250.64(A) through (F). (C) Continuous. The grounding electrode conductor shall be installed in one continuous length without a splice or joint, unless spliced only by irreversible compression-type connectors listed for the purpose or by the exothermic welding process.

-- Tom H