# UF in 1" Conduit Question

1707 Views 10 Replies 8 Participants Last post by  electures
I see that per this chart, 12-2 UF has a diameter of .1684. And if I understand correctly, conduit cannot be filled to more than 40% capacity.

I have 1" Schedule 40 PVC conduit. I've searched but haven't been able to determine the actual inside diameter of 1" PVC.

What I'd like to know is whether 3 pulls of 12-2 UF (with ground) would exceed the capacity of 1" PVC conduit, per code? I realize 3 pulls of UF in 1" would be difficult to accomplish. I just want to know if it's legal.

Thanks.

Tipsy
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It is easier to just pull THHN/THWN through the conduit. The only time that you will see UF inside a conduit, is to protect it where it comes out of the ground, to enter a junction box on the side of the structure, or inside the structure.

There is no way to get three runs of UF through even a 1", no matter how hard you tried. The jacket is just that stiff.
0.168 is the square inch area of a 12-2 UF cable. The nominal diameter is .463 inches.
NEC tables show 1" PVC having an inside area of .832 square inches.
A single conductor or cable is allowed a 53% fill of .575 square inches.
Two conductors or cables are allowed 31% fill of .258 square inches.
Over two conductors or cables are allowed 40% fill of .434 square inches.

Two cables would be over the 31% limit and three cables would be over the 40% limit.
1
0.168 is the square inch area of a 12-2 UF cable. The nominal diameter is .463 inches.
NEC tables show 1" PVC having an inside area of .832 square inches.
A single conductor or cable is allowed a 53% fill of .575 square inches.
Two conductors or cables are allowed 31% fill of .258 square inches.
Over two conductors or cables are allowed 40% fill of .434 square inches.

Two cables would be over the 31% limit and three cables would be over the 40% limit.
That's exactly what I needed to know.

Thank you.

Tipsy
That's exactly what I needed to know.

Thank you.

Tipsy
The limit has nothing to do in what you are doing. It is the fact that no one runs UF through conduit, unless it is to protect it where it exits the ground.

Stick with THHN/THWN, if you are going to run Conduit from points A & B. You will have to size your ground to the largest for all circuits.

If these lines are going to the same point. Easier to just pull 4 THHN/THWN and then use a panel for the three circuits.
The limit has nothing to do in what you are doing. It is the fact that no one runs UF through conduit, unless it is to protect it where it exits the ground.

Stick with THHN/THWN, if you are going to run Conduit from points A & B. You will have to size your ground to the largest for all circuits.

If these lines are going to the same point. Easier to just pull 4 THHN/THWN and then use a panel for the three circuits.
Wrong again, as usual.
The limit has nothing to do in what you are doing. It is the fact that no one runs UF through conduit, unless it is to protect it where it exits the ground.

Stick with THHN/THWN, if you are going to run Conduit from points A & B. You will have to size your ground to the largest for all circuits.

If these lines are going to the same point. Easier to just pull 4 THHN/THWN and then use a panel for the three circuits.
Conduit fill does matter with what the OP was proposing. The conduit would need to be sized to prevent damage to the cable.
I realize 3 pulls of UF in 1" would be difficult to accomplish. I just want to know if it's legal.
It depends in part, on where these 3 circuits are going. You are not allowed to run multiple 12-2 circuits to a detached structure.
2
I realize 3 pulls of UF in 1" would be difficult to accomplish. I just want to know if it's legal.
Legal and what is feasible are two different items.

Do yourself a favor and if possible DO NOT pull UF in conduit.
4
Is derating needed if UF is installed in conduit?
bob22 said:
Is derating needed if UF is installed in conduit?
Yes. Two cables and above.
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