• We will be performing upgrades on the forums and server over the weekend. The forums may be unavailable multiple times for up to an hour each. Thank you for your patience and understanding as we work to make the forums even better.

Maximum # Conductors in 1" EMT

A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
I know this but I'm getting two different answers based on a calculator and table C.1 Chapter 9.

Adhering to 30% fill

#10 THHN I get 12 in one and 16 in another. I assume the NEC table which says 16 is not taking 30% fill into consideration.
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Where are you coming up with 30% fill ?
Over two conductors is a 40% allowance.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Alwayslearningelec said:
#10 THHN I get 12 in one and 16 in another. I assume the NEC table which says 16 is not taking 30% fill into consideration.
Click to expand...
16 is the correct answer but as Augie stated the maximum fill percentage for 3 or more conductors is 40%. When is doubt you can always go old school and look at the physical Table C1 in Annex C.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Alwayslearningelec said:
Revisiting this. Do you guys ever really pull 16 #10's THHN in 1" EMT?
Click to expand...
I've seen it done as long as you use stranded conductors but imo it's not a good design unless the runs are very short. We once had a job spec of #10 solid and the lay out man had 18-#10's in a 1" EMT (he said grounds don't count). They has to use a super tugger to get the wire in and the force was so great that the large 45° offsets in the run near the tugger actually star started to straightened out.
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
infinity said:
I've seen it done as long as you use stranded conductors but imo it's not a good design unless the runs are very short. We once had a job spec of #10 solid and the lay out man had 18-#10's in a 1" EMT (he said grounds don't count). They has to use a super tugger to get the wire in and the force was so great that the large 45° offsets in the run near the tugger actually star started to straightened out.
Click to expand...
wow... I am surprise the wires didn't snap.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
electrofelon said:
Actually thinking about it, I bet that's pretty common that # 10 home runs are speced, so what do you guys usually do in that case for quantity and pipe size?
Click to expand...
I prefer 1.25" home runs. With #10's and 20 amp circuits you can get up to 20 CCC's without derating getting you below 20 amps.
 
You must log in or register to reply here.
Top