Dsg319
Senior Member
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- West Virginia
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- Wv Master “lectrician”
Conduit fill.
- Thread starter Dsg319
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wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Always round down? The allowances given for rounding up don't apply.
Cheers, Wayne
Cheers, Wayne
Dsg319
Senior Member
- Location
- West Virginia
- Occupation
- Wv Master “lectrician”
I started wondering if that was the case. It’s also the same with box fill too right?
kwired
Electron manager
- Location
- NE Nebraska
See notes to tables (note 7) at beginning of chapter 9
Dsg319
Senior Member
- Location
- West Virginia
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- Wv Master “lectrician”
to
texie
Senior Member
- Location
- Fort Collins, Colorado
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- Electrician, Contractor, Inspector
Yep, one of those strange but true quirks of the NEC.
kwired
Electron manager
- Location
- NE Nebraska
If you calculate a raceway can hold 6.7 conductors you are limited to 6 conuctors.
If you calculate a raceway can hold 6.8 or 6.9 conductors you can install 7.
different sizes just doesn't work out, If you have a 10 AWG and remaining room for 5.8 6 AWG's can you add an additional 6? an additional 10? This may seem simple but what if you have even more variety of sizes of conductors involved. Which one do you apply the fractional figure to when rounding up?
If you calculate a raceway can hold 6.8 or 6.9 conductors you can install 7.
different sizes just doesn't work out, If you have a 10 AWG and remaining room for 5.8 6 AWG's can you add an additional 6? an additional 10? This may seem simple but what if you have even more variety of sizes of conductors involved. Which one do you apply the fractional figure to when rounding up?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
I use an online conduit-fill calculator.
Dsg319
Senior Member
- Location
- West Virginia
- Occupation
- Wv Master “lectrician”
I’ve got one as well, though we usually work off of a set of prints where everything is already figured out and we just gotta put it together. And had been a while since I’ve done a calculation and still nice to know In my head how to do on paper for my own sake lol.
Dsg319
Senior Member
- Location
- West Virginia
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- Wv Master “lectrician”
If I understand your question correctly you could only add an additional 10awg of the same size with the fraction of 0.8 or greater.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
kwired
Electron manager
- Location
- NE Nebraska
But unless they are all the same size how do you know which one of the sizes you can round up?
If you have all 14 and 12, maybe not too big of a deal to add one or the other. If you have 3/0 and 4 AWG conductors in the raceway, adding one more 3/0 makes a bigger difference than adding one more 4 AWG.
When it is all same size and you come up with say 5.8 conductors is max fill, if you round that up to 6 the amount of "overfill" is pretty minimal, especially when dealing with a 40% fill being maximum in the first place other than one and two conductor applications.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If they are all the same size you are likely to use Table C which takes the .8 factor into consideration so it's kinda one of those nice thing s to know but useless
Hey I worked hard on that table and it was a pain getting that .8 to work. I believe I started a thread on that and got help on that issue from Smart $... Now I feel useless...
kwired
Electron manager
- Location
- NE Nebraska
Those tables are partially your fault? IMO all they do is add more pages to the book, I hardly have ever used them.
Anyone that runs enough raceway knows how many 14, 12 and 10 fit in most 1/2 and 3/4 raceways off top of their head anyway and maybe a few other common conductor and raceway applications are stuck in their head as well. If anything varies from those usual applications, go to chapter 9 and figure it out. If not all same size you are using chapter 9 regardless.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Thanks, I appreciate the helpful and atta boy compliments. Not everyone is as vain and as smart as you.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
He's so vain, he probably thinks that post is about him.
kwired
Electron manager
- Location
- NE Nebraska
Sorry if you were offended, I was shooting for a little sarcasm and not so much for smart ass-ism. Hard to convey that on a keyboard though.
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