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Conduit Wire Fill Charts & Tables

Chapman Electric offers a selection of pipe and conduit to meet your electrical or underground project needs. The NEC sets standards for the percent of volume that can safely be put into conduit. The below chart is from Table 1 in Chapter 9 of the National Electric Code.

Percent of Cross Section of Conduit and Tubing for Conductors

Number of ConductorsAll Conductor Types
1 53%
2 31%
More than 2 40%

Use the below charts to determine the number of wires that can be put into conduit tubing, while maintaining NEC standards.

ENT (Electrical Non-Metallic Tubing) Conduit Fill Tables

Maximum Number of Concentric Stranded Conductors in Electrical Nonmetallic Tubing (ENT)

TypeConductor Size1/2" (16mm)3/4" (21mm)1" (27mm)1-1/4" (35mm)1-1/2" (41mm)2" (53mm)
RHH, RHW, RHW-2 AWG/kcmil14 3 6 10 19 26 43
12 2 5 9 16 22 36
10 1 4 7 13 17 29
8 1 1 3 6 9 15
6 1 1 6 5 7 12
4 1 1 2 4 6 9
3 1 1 1 3 5 8
2 0 1 1 3 4 7
1 0 1 1 1 3 5
TW14 7 13 22 40 55 92
12 5 10 17 31 42 71
10 4 7 13 23 32 52
8 1 4 7 13 17
RHH*, RHW*, RHW-2*, THHW, THW, THW-214 4 8 15 27 37 61
RHH*, RHW*, RHW-2*, THHW, THW12 3 7 12 21 29 49
10 3 5 9 17 23 38
RHH*, RHW*, RHW-2*, THHW, THW, THW-28 1 3 5 10 14 23
RHH*, RHW*, RHW-2*, TW, THW, THHW, THW-26 1 2 4 7 10 17
4 1 1 3 5 8 13
3 1 1 2 5 7 11
2 1 1 2 4 6 9
1 0 1 1 3 4 6
1/0 0 1 1 2 3 5
2/0 0 1 1 1 3 5
3/0 0 0 1 1 2 4
4/0 0 0 1 1 1 3
250 0 0 1 1 1 2
300 0 0 0 1 1 2
350 0 0 0 1 1 1
400 0 0 0 1 1 1
500 0 0 0 1 1 1
600 0 0 0 0 1 1
700 0 0 0 0 1 1
750 0 0 0 0 1 1
800 0 0 0 0 1 1
900 0 0 0 0 0 1
1000 0 0 0 0 0 1
1250 0 0 0 0 0 0
1500 0 0 0 0 0 0
1750 0 0 0 0 0 0
2000 0 0 0 0 0 0
FEP, FEPB, PFA, PFAH, TFE14 10 18 31 56 77 128
12 7 13 23 41 56 93
10 5 9 16 29 40 67
8 3 5 9 17 23 38
6 1 4 6 12 16 27
4 1 2 4 8 11 19
3 1 1 4 7 9 16
2 1 1 3 5 8 13
THHN, THWN, THWN-214 10 18 32 58 80 132
12 7 13 23 42 58 96
10 4 8 15 26 36 60
8 2 5 8 15 21 35
6 1 3 6 11 15 25
4 1 1 4 7 9 15
3 1 1 3 5 8 13
2 1 1 2 5 6 11
1 1 1 1 3 5 8
1/0 0 1 1 3 4 7
2/0 0 1 1 2 3 5
3/0 0 1 1 1 3 4
4/0 0 0 1 1 2 4
250 0 0 1 1 1 3
300 0 0 1 1 1 2
350 0 0 0 1 1 2
400 0 0 0 1 1 1
500 0 0 0 1 1 1
600 0 0 0 1 1 1
700 0 0 0 0 1 1
750 0 0 0 0 1 1
800 0 0 0 0 1 1
900 0 0 0 0 1 1
1000 0 0 0 0 0 1
PFA, PFAH, TFE1 1 1 1 4 5 9
PFA, PFAH, TFE, Z1/0 0 1 1 3 4 7
2/0 0 1 1 2 4 6
3/0 0 1 1 1 3 5
4/0 0 1 1 1 2 4
Z14 12 22 38 68 93 154
12 8 15 27 48 66 109
10 5 9 16 29 40 67
8 3 6 10 18 25 42
6 1 4 7 13 18 30
4 1 3 5 9 12 20
3 1 1 3 6 9 15
2 1 1 3 5 7 12
1 1 1 2 4 6 10
XHH, XHHW, XHHW-2, ZW14 7 13 22 40 55 92
12 5 10 17 31 42 71
10 4 7 13 23 32 52
8 1 4 7 13 17 29
6 1 3 5 9 13 21
4 1 1 4 7 9 15
3 1 1 3 6 8 13
2 1 1 2 5 6 11
XHH, XHHW, XHHW-21 1 1 1 3 5 8
1/0 0 1 1 3 4 7
2/0 0 1 1 2 3 6
3/0 0 1 1 1 3 5
4/0 0 0 1 1 2 4
250 0 0 1 1 1 3
300 0 0 1 1 1 3
350 0 0 1 1 1 2
400 0 0 0 1 1 1
500 0 0 0 1 1 1
600 0 0 0 1 1 1
700 0 0 0 1 1 1
750 0 0 0 1 1 1
800 0 0 0 1 1 1
900 0 0 0 1 1 1
1000 0 0 0 0 0 1
1250 0 0 0 0 0 1
1500 0 0 0 0 0 1
1750 0 0 0 0 0 0
2000 0 0 0 0 0 0

Maximum Number of (Concentric Stranded Conductors) Fixture Wires in Electrical Nonmetallic Tubing (ENT)

[Additional tables continue with Fixture Wires, Compact Conductors, and Rigid PVC Conduit Schedule 80 specifications...]

Compact stranding is the result of a manufacturing process where the standard conductor is compressed to the extent that the interstices (voids between strand wires) are virtually eliminated

Information taken from NEC Appendix C, Tables C.2, C.2(A), and C.9