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Must All Ground Wires be Tied Together in Jbox ?

Posted by tom_in_seattle (My Page) on
Thu, Nov 19, 09 at 16:51

I'm going to have several 3-gang jboxes with three switches and a total of six 14-2 or 14-3 cables in/out.

Do all the ground wires need to be crimped or wire-nutted together as one... with a pigtail going to each switch, or can the ground wires associated with each particular switch circuit be crimped or wire-nutted together?

I'd like to use "Buchanans" to save room since most of the switches are either master or remote dimmers.

Thanks.


Follow-Up Postings:

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RE: Must All Ground Wires be Tied Together in Jbox ?

Must All Ground Wires be Tied Together in Jbox ? YES!


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RE: Must All Ground Wires be Tied Together in Jbox ?

OK, that was a concise answer :-)

Now, what if I have two (2) switches using 14 ga and one (1) receptacle using 12 ga? Can/should all those grounds be tied together or would it be better to put the recpetacle in its own jbox? If so, how is that any different than keeping the 14 and 12 ga grounds separate in the same jbox... other than one is legal and one I assume is not?


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RE: Must All Ground Wires be Tied Together in Jbox ?

So long as ALL the equipment grounding conductors are electrically connected to each other (and to the box if it is of conductive material), it meets code. For multi-gang boxes, I might use 3 or 4 crimp sleeves to connect all of them. Connect 3 plus pigtail, connect 3 more plus the pigtail, continue as necessary.


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RE: Must All Ground Wires be Tied Together in Jbox ?

Our local AHJ require crimping so I leave one ground out of the bundle long and tie that to all the switches


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RE: Must All Ground Wires be Tied Together in Jbox ?

hendricus' method would be fine for normal switches where you could wrap the ground wire around each ground screw and daisy-chain to the next, but the Leviton Acenti switches I'm using don't have an exposed ground screw... the wire is inserted in a slot from the rear and the screw tightens a metal clamp against the wire, thus I need a separate ground wire for each switch.


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RE: Must All Ground Wires be Tied Together in Jbox ?

"the wire is inserted in a slot from the rear and the screw tightens a metal clamp against the wire, thus I need a separate ground wire for each switch."

Many of the clamp plate systems are listed to accept two conductors (one on each side of the clamp screw) but check and also make sure if they are rated to clamp different sizes at the same time (like #14 & #12).

While pig tails are not counted in box fill, they sure can crowd things and make getting devices in difficult if there are a lot of them and a lot of excess wire.


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RE: Must All Ground Wires be Tied Together in Jbox ?

The ground wire clamping system on these master and remote dimmers only accepts a single ground wire.

Therefore, I think I may change the design layout and move the 20A SA receptacle from the 3-gang jbox to its own jbox and keep the two switches separate.

BTW, what's a good source and brand name for a Buchanan ground wire crimper that produces a 4-crimp connection?

Thanks.


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RE: Must All Ground Wires be Tied Together in Jbox ?

I have a metal 3 gang box, with two dimmers and a single switch. The gang has 6 ground screws at the bottom. I want to know if I can connect the ground conductor wires through a pigtail to one of the box ground screws and then the two green ground wires coming from the dimmers each to other separate box ground screws?
In fact all the grounds are connected to the box. Is it safe to do it like that?


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RE: Must All Ground Wires be Tied Together in Jbox ?

Splice all the grounds together along with a pigtail which is bonded to the box. This minimizes the chance that one or more of the conductors might later be disconnected by accident.


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RE: Must All Ground Wires be Tied Together in Jbox ?

I have to pigtail 7 wires. Is it going to pass an inspection if done as I suggested?


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RE: Must All Ground Wires be Tied Together in Jbox ?

Make two or three splices and include a pigtail in each to connect to the others plus one pigtail for the box. Multiple grounding screws in the box is not acceptable.


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RE: Must All Ground Wires be Tied Together in Jbox ?

"Multiple grounding screws in the box is not acceptable."

This would be using the box as a grounding conductor, and is NOT allowed.


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RE: Must All Ground Wires be Tied Together in Jbox ?

I don't know your location but it is acceptable in Canada To use multiple ground screws in a box or gang of boxes.


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RE: Must All Ground Wires be Tied Together in Jbox ?

wow... you guys must use a whole heck of a lot of wire nuts in gutters haha. i've never heard of such a practice.


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RE: Must All Ground Wires be Tied Together in Jbox ?

"To use multiple ground screws in a box or gang of boxes."

Multiple screws that leave the box acting as part of the grounding conductor, or just more than one screw for ganged boxes?


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RE: Must All Ground Wires be Tied Together in Jbox ?

A system that uses solely the metallic conduit or body of a/c cable would be using the metal boxes as conductors.


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RE: Must All Ground Wires be Tied Together in Jbox ?

So... in an "all-metallic" system (EMT + OLD WORK/existing MULTI-gang metal boxes), it IS or is NOT NEC-compliant to sink more than 1 self-tapping GND screws, to reduce clutter? (Presumbably because springy-type grounding straps on yokes aren't available, or don't mate w/ mud ring, or...?)


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RE: Must All Ground Wires be Tied Together in Jbox ?

"To use multiple ground screws in a box or gang of boxes."

Multiple screws that leave the box acting as part of the grounding conductor, or just more than one screw for ganged boxes?
I Canada boxes usually have two screws each. It is fine to any one of those for grounds. There is no requirement to tie all the grounds together by any other means.


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RE: Must All Ground Wires be Tied Together in Jbox ?

"self-tapping GND screws"

Self tapping screws are NOT allowed as ground connections.

A cut thread MUST be used.


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RE: Must All Ground Wires be Tied Together in Jbox ?

Self tapping screws are NOT allowed as ground connections.

A cut thread MUST be used.

How sad... wonder what the rationale is? For decades the rather tiny twin 6-32 yoke mounting screws were adequate GND bonding... presumably someone came to harm/death disproving that. =:O

So... are you saying when real sparkies encounter existing metal j-boxes in an EMT system, they drill and TAP a new hole? Laborious. Pretty sure my automotive tap & die set doesn't go down to 10-32... Yet Another tool for the New Year.


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RE: Must All Ground Wires be Tied Together in Jbox ?

Ground clips are handy for the old boxes that are left in place.


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RE: Must All Ground Wires be Tied Together in Jbox ?

"So... are you saying when real sparkies encounter existing metal j-boxes in an EMT system, they drill and TAP a new hole? Laborious."

You can purchase what looks like a screwdriver, but actually has taps for 6-32, 8-32, and 10-32 one after another up the length of the shaft.

Drill hole, tap as needed.

A self tapping screw does not make a 'gas tight' connection adequate for long term reliability.

The yoke mounting screws had the same problem since they might not be pulled up tight in every installation.

You need a screw that is tight against its threads to have a reliable gas tight long term connection.


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Cool...

Brick, thanks for the 411--both rationale and remedy.

Put yourself down for a New Year's bonus... derived from all the pop-up ads...


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RE: Must All Ground Wires be Tied Together in Jbox ?

To Joed.

I am in Canada.
Can I connect each ground wire to a different screw?
Thanks


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