Grounding wire multiple circuits.

[PoorOwner]

One conduit going to another (big) box with 3 sets of current carrying wires.
Can I just run one ground wire then split the ground at the box instead of running 3 ground wires ?
How to size this ground wire ?

Actually, it’s emt so the box and conduit are grounded. I could have taken ground from the box without running ground wire. But just wanted to run one.

 

[Firebrick43]

Size the wire for the largest circuit. For example if you have 2 15 amp conductors(14ga) and 1 20 amp (12ga) you would use a 12ga ground.

However you description rings some bells. This "big box" is not a sub panel is it?

 

[Norcal]

Pull a grounding conductor the same size as your largest conductor, no need to run 3.

 

[teamextreme]

Only need one wire, sized to the size of the largest circuit. I would just use the EMT, but nothing wrong with pulling a separate grounding conductor.

 

[PoorOwner]

Thanks. Big Box just helps me turn and branch off additional conduits.
Maybe 4 9/16 box

 

[alfredeneuman]

Maybe 4 9/16 box

There's no such thing as 4-9/16 box
Didn't you mean a 4-11/16 box?

 

[sberry]

Use a deeper instead of a bigger box. I try to use as much common as I can, can keep extra in stock and have a future use for it.

 

[alfredeneuman]

You only need 1 grounding conductor.
The largest size circuit will determine that.
15A a #14
20A a #12
30-60A a #10
60-100 a #8
If you have any conduits that comes out of the box, you can tap off a larger wire with smaller according to the the largest circuit in that particular conduit.

 

[PoorOwner]

You only need 1 grounding conductor.
The largest size circuit will determine that.
15A a #14
20A a #12
30-60A a #10
60-100 a #8
If you have any conduits that comes out of the box, you can tap off a larger wire with smaller according to the the largest circuit in that particular conduit.

thanks, and I do mean 4-11/16 box... they have more space, but options for covers etc are limited

 

[dscheidt]

thanks, and I do mean 4-11/16 box... they have more space, but options for covers etc are limited

https://www.garvinindustries.com/covers-and-device-rings/4-11-16-in-square-covers-device-rings

What isn't available?

 

[sberry]

They are available, just not as common and I am in this class of use, never needed one in common garage work. Never. Got a whole box of various common 4 inch covers that can and will get used. I am sure someone has had a different experience and industrial is another matter but the most biggest stuff is 6 wire and not every wire in the place has to run down a single pipe.

 

[sberry]

Last welder recept I added or moved was a single circuit in about 4 ft of 1/2 pipe right to the panel, 3 number 10. I got 3 or so that way and a couple 6 in 3/4 , only a couple share a pipe. They are for 200 mig.
I have NEVER had or needed to come back and run a new welder wire down a pipe I had for a common outlet or switch loop.