Calculating fill for LFNC-B

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crtemp

Senior Member
Location
Wa state
I'm trying to figure out if three #6 THHN and one #8 THHN can fit in 1'' LFNC-B. I see in the tables section of the NEC that 1'' liquid tight conduit has area of .349 sq inches at 40%.

I also see that #6 THHN has an area of .0507 sq inches and #8 THHN has an area of .0366 sq inches.

When I add up all of the wires I come up with .1887 sq inches, which is less than the .349 sq inches allowed for the conduit, so I'm thinking I'm good to go...

Am I doing this correctly?

Also what about the fittings? Does the same sq inches apply to those as the 1'' conduit?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
a shortcut would be to look at Table 5 which will show you that 1" LFNC-B will accommodate (7) #6 THHNs so you obviously are good to go.
Fittings will not alter you findings.
FWIW, your calculations looked 100%
 
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crtemp

Senior Member
Location
Wa state
a shortcut would be to look at Table 5 which will show you that 1" LFNC-B will accommodate (7) #6 THHNs so you obviously are good to go.
Fittings will not alter you findings.

For some reason I had thought that Table said I was only allowed 4 #6 wires in 1'' conduit so that was why I thought adding it all up seemed wrong when it came out to only being about half full. I now see that it says 7 #6's can fit.

Thank you
 
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