Box fill calculation

[TRamsay]

When calculating box fill, is it required to count wire nuts as part of the fill. And if so, which article would describe this.
314.16B mentions clamps, support fittings, and such but I don't see any mention of splicing devices such as wire nuts.
Any help would be appreciated, with code article where this is mentioned of course.
Thank you.

 

[ryan_618]

Re: Box fill calculation

Wire nuts do not need to be counted.

 

[TRamsay]

Re: Box fill calculation

Thank you Ryan for your reply.

 

[jes25]

Re: Box fill calculation

IMO the box fill calcs are stupid. Hmmmmm...Wire nuts take up no space, and a GFI or Dimmer doesn't take up more than a S.P. :roll:


Nevermind if it's changed it would only be harder.

 

[jimwalker]

Re: Box fill calculation

Your smart if you allow space for the above.Keep in mind its you thats gotta trim it.NEC is the min. i prefer to go over.

 

[jes25]

Re: Box fill calculation

My point is this. Lets say we have a 18 cubic in. box

4 #14 nm with a single pole switch = violation

3 #14 nm with a 1000 watt dimmer and cables entering top, bottom and back with a couple jumpers and a couple red wirenuts = Approved

Which box is a easier install or safer or better. I realize they are both bad I would not do either but the second is WORSE IMO, yet approved. :roll:

 

[Mike The Mute]

I know how confusing 314.16 can be. Going into a round nail-on that allows 11 #14, I have two 3wires and two two wires. The box is filled to capacity by the wire: 3+3+2+2+1(ground)=11. The box will have a lightfixture installed to it with factory supplied wiring, so there is no need to add for the device. Will it pass, or will it fail? To top things off, one of the 3wires is a home run that seperates at the round nail-on. Seems to be a forbidden practice in these parts, but accepted where I'm from. Accepted by both codes 210.4(b) and 300.13(b) too.
I am always looking at my box fill because I have failed for being one over. The way I was taught to count box fill was every wire except grounds get counted individually, all grounds as 1, and each device as two. I haven't heard an inspector translate 314.16 to the contrary.
Let me know if you have.

 

[infinity]

The way I was taught to count box fill was every wire except grounds get counted individually, all grounds as 1, and each device as two. I haven't heard an inspector translate 314.16 to the contrary.

This is correct. I would add that the wires that don't leave the box do not get counted.

one of the 3wires is a home run that seperates at the round nail-on. Seems to be a forbidden practice in these parts, but accepted where I'm from.

Why would this be forbidden?

 

[Mike The Mute]

Thank you for the support. According to 314.16, Pigtailed wires from the box and fewer than 4 wires no smaller than 14awg coming from the fixture do not have to be counted.
As for the 3wire homerun, I have no idea why it would be a problem, but apparently it is with the inspectors in this region. Guess I'll find out more on Monday during the inspection. Not only does code allow this practice, but with the price of copper, it should be applied as often as possible. The best way to keep us working when material costs are through the roof, is to reduce material.

 

[tonyi]

The way I was taught to count box fill was every wire except grounds get counted individually, all grounds as 1, and each device as two.

Pull-throughs only count as one too (unless they're looped around). If you're roping rather than piping, that's never gonna happen though.

 

[jwelectric]

The way I was taught to count box fill was every wire except grounds get counted individually, all grounds as 1, and each device as two.

Pull-throughs only count as one too (unless they're looped around). If you're roping rather than piping, that's never gonna happen though.

Why Not :?:

 

[infinity]

The way I was taught to count box fill was every wire except grounds get counted individually, all grounds as 1, and each device as two.

Pull-throughs only count as one too (unless they're looped around). If you're roping rather than piping, that's never gonna happen though.

Why Not :?:

Well for one thing if you're only roping cables than you won't be pulling conductors through a conduit. I would add that looped conductors only count for more than one conductor after they have exceeded twice the length required for free conductors in 300.14.

 

[russ]

box fill

box fill

Box fill may seem silly in some instances, but with no limitations we would have a real mess.
Over fill is a very common practice.
It is a frequent found violation, probably in the top 20 or 30.

Had one the other day 4 x 4 x 2 1/8 = 30.3 cubic in.
The mix fill came up to 47 cubic in.

 

[Mike The Mute]

If you think no limits MAY be a mess. Take a stroll through parts of North Georgia. One County has only been pulling permits for two years. In a year of new construction in that area, I only saw a print twice. One General Contractor didn't know what Dimensions were. Same builder looked for a gas leak with, you guessed it, a lighter!
Service calls are like nightmares. You close your eyes and hope the place is burned down by the time you open them.
Some codes are a pain and some are just plain stupid (One inspector told me that in a flood zone portion of a particular house, the GFCI went below flood and the protected outlets above). In the end, code keeps those that shouldn't be in this trade from killing the people that live in their houses.

 

[tonyi]

The way I was taught to count box fill was every wire except grounds get counted individually, all grounds as 1, and each device as two.

Pull-throughs only count as one too (unless they're looped around). If you're roping rather than piping, that's never gonna happen though.

Why Not :?:

Strictly speaking I suppose it could be done, but it would be a real PITA to get the 2nd half of the cable through the box from the inside. Feeding through a black button or Carlon clamp backwards is tough.

I think I'd use a bigger box before resorting to such tortures :lol: