Device box also used to pull another circuit “thru”

[Shovelhead]

What’s the NEC code cops say about this?
I‘m running two 240v circuits, #10 THWN in ENT.
Circuit 1 will terminate in a 4S box to feed a Dust Collector.
Circuit 2 will feed two other 4S boxes for woodworking tools that will only be operated one at a time.

The feed for both circuits is entering the same wall.
I want to use the box for circuit 1 to pull circuit 2 wiring through.

10-4 ?

 

[dscheidt]

Universal practice where conduit is in use. All grounds need to be tied together in every box, and all metal boxes grounded. You only need a single ground wire, sized for the largest circuit in the conduit.

 

[Shovelhead]

so you’re saying pull 5 conductors from the panel to the first device box(circuit 1) and pick up circuit 2 ground out of that box?

 

[sparky 1971]

so you’re saying pull 5 conductors from the panel to the first device box(circuit 1) and pick up circuit 2 ground out of that box?

Just make sure the ground is sized for the largest circuit. Try to pull the additional circuits through the box without splicing them. The ground will have to be spliced, but cutting down on the number of wire nuts sure makes it a lot easier to get everything jammed back into the box.

 

[Shovelhead]

Yeah that was my main question. Didn’t know if it was allowed to pull another circuit through a box with a device(240v receptacle) in it, or any reason not to.
I always want to do things “right” , but Safety and reliability reasons are my concerns with any wiring I’m doing in my shop.
We’re in the sticks. The code here is my code.



Is it any different if a feller was using romex?

 

[Shovelhead]

Eliminating a junction box and splicing one of the circuits is the reason I figgered I’d do it this way.

 

[sparky 1971]

Yeah that was my main question. Didn’t know if it was allowed to pull another circuit through a box with a device(240v receptacle) in it, or any reason not to.
I always want to do things “right” , but Safety and reliability reasons are my concerns with any wiring I’m doing in my shop.
We’re in the sticks. The code here is my code.



Is it any different if a feller was using romex?

Unless it's 100% straight and not very long, there's no way I'd try to pull more than one romex through, especially #10. Trying to pull a total of six #10 solid wires through anything smaller than a 1" is a monumental task, throw the romex jacket on top of everything else and it all adds up to you are a much harder worker than I ever was. You'd also probably never get the second romex to feed through the first box and wind up having to splice.

Get some #10 THHN/THWN, two hot colors and a green. Say black and red, cut one set long enough to reach the first box, leave the second set and the ground on the spools. Pull everything to the first box, fold set #1 back and pull the second set on through to the second box. Then go back to box #1 and pull out a loop of ground.

 

[dscheidt]

Is it any different if a feller was using romex?

When putting romex in conduit, you have to consider the whole cable size when calculating fill, which means you can run a single 12/2 in 3/4 emt (or something like that, I'm not in the mood to work it out, it's huge stuff, though). It's also stupidly stiff and and hard to pull. You also can't use it any where wet (outdoors, underground) even in conduit. Pulling THHN is easier and typically about the same money, and if you don't want to buy a spool, you can install your conduit, measure your conductor lengths, and buy exactly what you need. (for 12/14, buy a spool, bigger you can buy lengths from most sellers of wire.)

 

[Shovelhead]

No no no. LOL
Y’all misunderstood.
I ain’t even thinking about using romex. As I said , I’m using #10 THWN.
I was just curious if per NEC you can run a circuit of romex thru a device box same as I’m doing here. Not romex in conduit. Ive never run across having to do that before, so just asking.

I will tell you this, that F’n Smurf is a ***** kitty to deal with.
When I first unwrapped that hunnerd foot roll and started tryin to lay it out on the shop floor I thought it was going knock over a motorcycle, a step ladder, poke a hole in my boat and break my nose.

When I finally got it laid out and strapped to the metal wall girts and inside the wood framed room I’m running it to, the shop vac couldn’t **** my string the whole distance.
Ended up having to cut it about halfway and incorporate an LB to use as a pull box.

Several curse words and 2 pulls off the Jack bottle later, I gotter done.

Thanks,

and sparky, I always value your take on things. Obvious to me you go about things with a true common sense approach. Happy New Year man.

 

[dscheidt]

No no no. LOL
Y’all misunderstood.
I ain’t even thinking about using romex. As I said , I’m using #10 THWN.
I was just curious if per NEC you can run a circuit of romex thru a device box same as I’m doing here. Not romex in conduit. Ive never run across having to do that before, so just asking.

You can, if there's room in the box. It's not common, since you can run romex past the box, but you do see it occasionally, with a loop of wire, so something can be installed later.

 

[exranger06]

You can absolutely pull more than one circuit through a conduit and junction/device box. Keep in mind though that you have to derate the ampacity of the wire when there are more than 3 current carrying conductors in the conduit (310.15(C)(1)), so make sure #10 is still sufficient, or you may need to upsize the wire. 4-6 current carrying conductors in a conduit will reduce the ampacity to 80%, or 32 A for #10 wire. 7-9 conductors reduces ampacity to 70%, or 28 A for #10. Also, if the ambient temp is going to be greater than 86 degrees F, you'll need to derate the conductors even more (310.15(B)). Also, keep box fill in mind and make sure your boxes are big enough for the amount of wires in them (314.16). And I'm not talking about just making sure you can physically cram the wires in the box. You need to do a box fill calculation.