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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
Size		1/2" (16mm)3/4" (21mm)1" (27mm)1-1/4" (35mm)1-1/2" (41mm)2" (53mm)
RHH, RHW, RHW-2
AWG/kcmil		14 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-2		14 4 8 15 27 37 61
RHH*, RHW*, RHW-2*,
THHW, THW		12 3 7 12 21 29 49
10 3 5 9 17 23 38
RHH*, RHW*, RHW-2*,
THHW, THW, THW-2		8 1 3 5 10 14 23
RHH*, RHW*, RHW-2*,
TW, THW, THHW, THW-2		6 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, TFE		14 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, Z		1/0 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, ZW		14 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)

TypeConductor
Size		1/2" (16mm)3/4" (21mm)1" (27mm)1-1/4" (35mm)1-1/2" (41mm)2" (53mm)
FFH-2, RFH-2, RFHH-3
SF-2, SFF-2		18 6 12 21 39 53 88
16 5 10 18 32 45 74
18 8 15 27 49 67 111
16 7 13 22 40 55 92
14 5 10 18 32 45 74
SF-1, SFF-118 15 28 48 86 119 197
RFH-1, RFHH-2, TF,
TFF, XF, XFF		18 11 20 35 64 88 145
RFHH-2, TF, TFF,
XF, XFF		16 9 16 29 51 71 117
XF, XFF14 7 13 22 40 55 92
TFN, TFFN18 18 33 57 102 141 233
16 13 25 43 78 107 178
PF, PFF, PGF, PGFF,
PAF, PTF, PTFF, PAFF		18 17 31 54 97 133 221
16 13 24 42 75 103 171
14 10 18 31 56 77 128
ZF, ZFF, ZHF,
HF, HFF		18 22 40 70 125 172 285
16 16 29 51 92 127 210
14 12 22 38 68 93 154
KF-2, KFF-218 31 58 101 182 250 413
16 22 41 71 128 176 291
14 15 28 49 88 121 200
12 10 19 33 60 83 138
10 7 13 22 40 55 92
KF-1, KFF-118 38 69 121 217 298 493
16 26 49 85 152 209 346
14 18 33 57 102 141 233
12 12 22 38 68 93 154
10 7 14 24 44 61 101
XF, XFF12 3 7 12 21 29 49
10 3 5 9 17 23 38

2-hour fire-rated RHH cable has ceramifiable insulation which has much larger diameters than other RHH wires. Consult manufacturer’s conduit fill tables. *Types RHH, RHW, and RHW-2 without outer covering.

Information taken from NEC Appendix C, Table C.2

Maximum Number of Compact Conductors in Electrical Nonmetallic Tubing (ENT)

TypeConductor
Size		1/2" (16mm)3/4" (21mm)1" (27mm)1-1/4" (35mm)1-1/2" (41mm)2" (53mm)
THW, THW-2, THHW8 1 3 6 11 15 25
6 1 2 4 8 11 19
4 1 1 3 6 8 14
2 1 1 2 4 6 10
1 0 1 1 3 4 7
1/0 0 1 1 3 4 6
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
900 0 0 0 0 1 1
1000 0 0 0 0 0 1
THHN, THWN,
THWN-2		8 0 0 0 0 0 0
6 1 4 7 12 17 28
4 1 2 4 7 10 17
2 1 1 3 5 7 12
1 1 1 2 4 5 9
1/0 1 1 1 3 5 8
2/0 0 1 1 2 4 6
3/0 0 1 1 1 3 5
4/0 0 1 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 2
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
900 0 0 0 0 1 1
1000 0 0 0 0 1 1
XHHW, XHHW-2
THWN-2		8 2 4 8 14 19 32
6 1 3 6 10 14 24
4 1 2 4 7 10 17
2 1 1 3 5 7 12
1 1 1 2 4 5 9
1/0 1 1 1 3 5 8
2/0 0 1 1 3 4 7
3/0 0 1 1 2 3 5
4/0 0 1 1 1 3 4
250 0 0 1 1 1 3
300 0 0 1 1 1 3
350 0 0 1 1 1 3
400 0 0 1 1 1 2
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
900 0 0 0 0 1 1
1000 0 0 0 0 1 1

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, Table C.2(A)

 

Maximum Number of Conductgors in Rigid PVC Conduit, Schedule 80

TypeConductor
Size		1/2"
(16
mm)		3/4"
(21
mm)		1"
(27
mm)		1-1/4"
(35
mm)		1-1/2"
(41
mm)		2"
(53
mm)		2-1/2"
(63
mm)		3"
(78
mm)		3-1/2"
(91
mm)		4"
(103
mm)		5" (129
mm)		6" (155
mm)
RHH, RHW, RHW-214 3 5 9 17 23 39 56 88 118 153 243 349
12 2 4 7 14 19 32 46 73 98 127 202 290
10 1 3 6 11 15 26 37 59 79 103 163 234
8 1 1 3 6 8 13 19 31 41 54 85 122
6 1 1 2 4 6 11 16 24 33 43 68 98
4 1 1 1 3 5 68 12 19 26 33 53 77
3 0 1 1 3 4 7 11 17 23 29 47 67
2 0 1 1 13 4 6 9 14 20 25 41 58
1 0 1 1 1 2 4 6 9 13 17 27 38
1/0 0 0 1 1 1 3 5 8 11 15 23 33
2/0 0 0 1 1 1 3 4 7 10 13 20 29
3/0 0 0 0 1 1 1 3 6 8 11 17 25
4/0 0 0 0 1 1 2 3 5 7 9 15 21
250 0 0 0 1 1 1 2 4 5 7 11 16
300 0 0 0 1 1 1 2 3 5 6 10 14
350 0 0 0 1 1 1 1 3 4 5 9 13
400 0 0 0 0 1 1 1 3 4 5 8 12
500 0 0 0 0 1 1 1 2 3 4 7 10
600 0 0 0 0 0 1 1 1 3 3 6 8
700 0 0 0 0 0 1 1 1 2 3 5 7
750 0 0 0 0 0 1 1 1 2 3 5 7
800 0 0 0 0 0 1 1 1 2 3 4 7
1000 0 0 0 0 0 1 1 1 1 2 4 5
1250 0 0 0 0 0 0 1 1 1 1 3 4
1500 0 0 0 0 0 0 1 1 1 1 2 4
1750 0 0 0 0 0 0 0 1 1 1 2 3
2000 0 0 0 0 0 0 0 1 1 1 1 3
TW14 6 1 20 35 49 82 118 185 250 324 514 736
12 5 9 15 27 38 63 91 142 192 248 394 565
10 3 6 11 20 28/td> 47 67 106 143 185 294 421
8 1 3 6 11 15/td> 26 37 59 79 103 163 234
RHH*, RHW*, RHW-2*,
THHW, THW, THW-2		14 4 8 13 23 32 55 79 123 166 215 341 490
RHH*, RHW*, RHW-2*,
THHW, THW		12 3 6 10 19 26 44 63 99 133 173 274 394
10 2 5 8 15 20 34 49 77 104 135 214 307
RHH*, RHW*, RHW-2*,
THHW, THW, THW-2		18 1 3 5 9 12 20 29 46 62 81 128 184
RHH*, RHW*, RHW-2*,
TW, THW, THHW, THW-2		6 1 1 3 7 9 16 22 35 48 62 98 141
4 1 1 3 5 7 12 17 16 35 46 73 105
3 1 1 2 4 6 10 14 22 30 39 63 90
2 1 1 1 3 5 8 12 19 26 33 53 77
1 0 1 1 2 3 6 8 13 18 23 37 54
1/0 0 1 1 1 3 5 7 11 15 20 32 46
2/0 0 1 1 1 2 4 6 10 13 17 27 39
3/0 0 0 1 1 1 3 5 8 11 14 23 33
4/0 0 0 1 1 1 3 4 7 9 12 19 27
250 0 0 0 1 1 2 3 5 7 9 15 22
300 0 0 0 1 1 1 3 5 6 8 13 19
350 0 0 0 1 1 1 2 4 6 7 12 17
400 0 0 0 1 1 1 2 4 5 7 10 15
500 0 0 0 1 1 1 1 3 4 5 9 13
600 0 0 0 0 1 1 1 2 3 4 7 10
700 0 0 0 0 1 1 1 2 3 4 6 9
750 0 0 0 0 0 1 1 1 3 4 6 8
800 0 0 0 0 0 1 1 1 3 3 6 8
900 0 0 0 0 0 1 1 1 2 3 5 7
1000 0 0 0 0 0 1 1 1 2 3 5 7
1250 0 0 0 0 0 1 1 1 1 2 4 5
1500 0 0 0 0 0 0 1 1 1 1 3 4
1750 0 0 0 0 0 0 1 1 1 1 3 4
2000 0 0 0 0 0 0 1 1 1 1 2 3
THHN, THWN, THWN-2<14 9 17 28 51 70 118 170 265 358 464 736 1055
12 6 12 20 37 51 86 124 193 261 338 537 770
10 4 7 13 23 32 54 78 122 164 213 338 485
8 2 4 7 13 18 31 45 70 95 123 195 279
6 1 3 5 9 13 22 32 51 68 89 141 202
4 1 1 3 6 8 14 20 31 42 54 86 124
3 1 1 3 5 7 12 17 26 35 46 73 105
2 1 1 2 4 6 10 14 22 30 39 61 88
1 0 1 1 3 4 7 10 16 22 29 45 65
1/0 0 1 1 2 3 6 9 14 18 24 38 55
2/0 0 1 1 1 3 5 7 11 15 20 32 46
3/0 0 1 1 1 2 4 6 9 13 17 26 38
4/0 0 0 1 1 1 3 5 8 10 14 22 31
250 0 0 1 1 1 3 4 6 8 11 18 25
300 0 0 0 1 1 1 3 5 7 9 15 22
350 0 0 0 1 1 1 3 5 6 8 13 19
400 0 0 0 1 1 1 3 4 6 7 12 17
500 0 0 0 1 1 1 2 3 5 6 10 14
600 0 0 0 0 1 1 1 3 4 5 8 12
700 0 0 0 0 1 1 1 2 3 4 7 10
750 0 0 0 0 1 1 1 2 3 4 7 9
800 0 0 0 0 1 1 1 2 3 4 6 9
900 0 0 0 0 0 1 1 1 3 3 6 8
1000 0 0 0 0 0 1 1 1 2 3 5 7
FEP, FEPB, PFA,
PFAH, TFE		14 8 16 27 49 68 115 164 257 347 450 714 1024
12 6 12 20 36 50 84 120 188 253 328 521 747
10 4 8 14 26 36 60 86 135 182 235 374 536
8 2 5 8 15 20 34 49 77 104 135 214 307
6 1 3 6 10 14 24 35 55 74 96 152 218
4 1 2 4 7 10 17 24 38 52 67 106 153
3 1 1 3 6 8 14 20 32 43 56 89 127
2 1 1 3 5 7 12 17 26 35 46 73 105
PFA, PFAH, TFE1 1 1 1 3 5 8 11 18 25 32 51 73
PFA, PFAH,
TFE, Z		1/0 0 1 1 3 4 7 10 15 20 27 42 61
2/0 0 1 1 2 3 5 8 12 17 22 35 50
3/0 0 1 1 1 2 4 6 10 14 18 29 41
4/0 0 0 1 1 1 4 5 8 11 15 24 34
Z14 10 19 33 59 82 138 198 310 418 542 860 1233
12 7 14 23 42 58 98 141 220 297 385 610 875
10 4 8 14 26 36 60 86 135 182 235 374 536
8 3 5 9 16 22 38 54 85 115 149 236 339
6 2 4 6 11 16 26 38 60 80 104 166 238
4 1 2 4 8 11 18 26 41 55 72 114 164
3 1 2 3 5 8 13 19 30 40 52 83 119
2 1 1 2 5 6 11 16 25 33 43 69 99
1 0 1 2 4 5 9 13 20 27 35 56 80
XHH,
XHHW,
XHHW-2,
ZW		14 6 11 20 35 49 82 118 185 2502 324 514 736
12 5 9 15 27 38 63 91 142 192 248 394 565
10 3 6 11 20 28 47 67 106 143 185 294 421
8 1 3 6 11 15 26 37 59 79 103 163 234
6 1 2 4 8 11 19 28 43 59 76 121 173
4 1 1 3 6 8 14 20 31 42 55 87 125
3 1 1 3 5 7 12 17 26 36 47 74 106
2 1 1 2 4 6 10 14 22 30 39 62 89
XHH,
XHHW,
XHHW-2		1 0 1 1 3 4 7 10 16 22 29 46 66
1/0 0 1 1 2 3 6 9 14 19 24 39 56
2/0 0 1 1 1 3 5 7 11 16 20 32 46
3/0 0 1 1 1 2 4 6 9 13 17 27 38
4/0 0 0 1 1 1 3 5 8 11 14 22 32
250 0 0 1 1 1 3 4 6 9 11 18 26
300 0 0 1 1 1 2 3 5 7 10 15 22
350 0 0 0 1 1 1 3 5 6 8 14 20
400 0 0 0 1 1 1 3 4 6 7 12 17
500 0 0 0 1 1 1 2 3 5 6 10 14
600 0 0 0 0 1 1 1 3 4 5 8 11
700 0 0 0 0 1 1 1 2 3 4 7 10
750 0 0 0 0 1 1 1 2 3 4 6 9
800 0 0 0 0 1 1 1 1 3 4 6 9
900 0 0 0 0 0 1 1 - 3 3 5 8
1000 0 0 0 0 0 1 1 1 2 3 5 7
1250 0 0 0 0 0 1 1 1 1 2 4 6
1500 0 0 0 0 0 0 1 1 1 1 3 5
1750 0 0 0 0 0 0 1 1 1 1 3 4
2000 0 0 0 0 0 0 1 1 1 1 2 4

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, Table C.9