Fill Calculation Question

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1793

1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
I have two questions about fill calculations.

1. How does one count a dead-end 3-Way with regard to Conduit Fill. I would say there are only two current carrying conductors. The travelers just alternate.

2. How would one calculate Box Fill with the same scenario? Again, I see just two.

As always I await anyones input.

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Re: Fill Calculation Question

Calculating box fill or conduit fill has nothing to do with what is or is not a current carrying conductor. That is only taken into consideration for derating purposes. You must count all conductors, regardless of what they are there for.
 
Re: Fill Calculation Question

Thanks Bryan. I thought I had something out of wack. So now that I'm back on track, how would it figure in to derating?

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Re: Fill Calculation Question

Also makes no since that a device is counted as 2 nomatter what it is.Could be a 50 cent single pole switch or a gfci receptacle.No allowance for excessive wire length either,or sloppy or neat work.Then again exsplain how a device gets bigger on #12 than it was on #14 ;)
 
Re: Fill Calculation Question

The device used to be counted as one I think it changed to two in 1987. The devices got bigger.

The 2005 requires additional cu in allowance where the length of looped conductors is twice that required by 300.14

A looped unbroken conductor not less than twice the minimum length of 300.14 shall be counted twice.

Extra conductor in an enclosure is subjective 300.14 requires at least 6" if the wires is getting in the way that becomes technic!!

Charlie
 
Re: Fill Calculation Question

Ever try to fit a GFCI device in a 4 sq. fiber box ?Allowed yes !!! Good practice,not in my book :eek:
 
Re: Fill Calculation Question

Side note : As of 2002 we are required to use Uf in any conduit under slabbed,So to make it easier for the GUYS ;) I said to J box behind the fridge or a pantry.change over to UF and feed knee wall island.When just a center island no problem.12/2 to 12/2 unless there is a close receptacle to come off of.Go to a knee wall island that has d/w disposal GFCI and faces a common area.Up sized the conduit to accomodate the amount of cable assys.We stock 12/2 uf and I told the guys to use the 12/2 uf for common area receptacle feed used a 2 gang Slater box and was tagged for box overfill.Now we have to use a 3 gang or a 2 gang and a 1 gang.Do the math it is a bit over but there is no device just splices.This is out of hand.To those that have followed my posts it is the same AHJ.Can I say he isn`t within NEC guide lines no but this is the height of nit picking.I have been in trade since 73 would never install anything that would be a hazard.But this guy red tags a job when the painters take off plates in a kitchen and reinstall them with the gfci sticker on the nook receptacle and the counter top without it.After all mrs. H/O`r will take the stickers off when moved in.Just at the end of my patience with this guy ;)
 
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