Conduit Capacity Chart


How to Use Selector

The maximum number of cables that each conduit size may contain to conform with National Electric Code Standards are given below. To find the conduit size required for cables where the O.D. is not shown and for combinations of different size cables, follow these steps:

1. Square the O.D. of each cable and total the results.
2. Multiply the total by .7854. This is the total area of the cables in square inches. (See note.)
3. From Actual Area (*), select a conduit size with area equal to or greater than the total area.

NOTE: Actual area to be occupied (sq. in.) National Electric Code Standard based on 40% fill applies to installation of 3 or more cables in a conduit. A single cable is permitted to occupy 53% and two cables are limited to 31% conduit fill. For a singles cable, use .5927 in step 2; for two cables, use 1.0134; for three or more cables, use .7854.

Installation Suggestions

This chart is based on the maximum number of cables permitted in conduit under the National Electric Code, and is calculated on the area of the cables with 40% of the conduit filled. *For conduit runs of 50 to 100 feet, the installed number should be reduced by 15%, or use the next size larger conduit. Each 90° conduit bend may be estimated as equal to the friction of 30 feet of straight level conduit. If more than two 90° bends are to be used in the conduit run, or if the run is to be over 100 feet in length, insert a pull box. The use of anti-friction agents is recommended during pulling operations.
Caution: Be sure the anti-friction agent selected is compatible with the cable jacket material. (Check the label.)

Installation Tips

In general, high and low level signals (mike and speaker wire, telephone and speaker wire) should never be run in the same conduit without obtaining engineering advice. Unshielded 300 ohm antenna lead-in wire should not be run in metallic conduits. The national Electric Code forbids the installation of communication cables in the same conduit with power cables.

Pulling Tensions

Annealed copper will begin to permanently elongate (stretch) under a stress of approximately 15,000 lbs./sq. in. The following table lists the absolute maximum recommended pulling tensions for specific conductor sizes. For multi-conductor cables, multiply the appropriate value by the total number of conductors. During installation the total pulling tension must be equally distributed among all conductors.

24 AWG - 4 lbs.
22 AWG - 7 lbs.
20 AWG - 12 lbs.
18 AWG - 19 lbs.
16 AWG - 30 lbs.
14 AWG - 48 lbs.
12 AWG - 77 lbs.


These limits must not be exceeded even momentarily. (Don't jerk cable.)

This table calculates the number of cables one can put into an EMT conduit exactly like the Dynamic Conduit Capacity Chart.

Calculations are not rounded until the "number of cables" is to be determined.
All values with fractional portions greater than or equal to 0.80 are rounded up.
All values with fractional portions less than 0.80 are rounded down (including 0.799999).

Click here for a Printable Version of the Conduit Capacity Chart.

Trade Size

1/2

3/4

1

1-1/4

1-1/2

2

2-1/2

3

3-1/2

4

Calc Cable Area

Cable OD

Internal Dia.

0.622

0.824

1.049

1.38

1.61

2.067

2.731

3.356

3.834

4.334

Calc area 40%

0.12154

0.21331

0.34570

0.59828

0.81433

1.34224

2.34311

3.53829

4.61800

5.90102

Calc area 31%

0.09420

0.16531

0.26792

0.46367

0.63111

1.04024

1.81591

2.74217

3.57895

4.57329

Calc area 53%

0.16104

0.28263

0.45805

0.79273

1.07899

1.77847

3.10462

4.68823

6.11885

7.81886

Max. # Cables

15

27

44

76

103

171

298

450

588

751

0.00785

0.100

14

24

40

69

94

155

270

408

533

681

0.00866

0.105

12

22

36

63

85

141

246

372

486

621

0.00950

0.110

11

20

33

57

78

129

225

340

444

568

0.01039

0.115

10

19

30

53

72

118

207

313

408

521

0.01131

0.120

10

17

28

48

66

109

191

288

376

481

0.01227

0.125

9

16

26

45

61

101

176

266

348

444

0.01327

0.130

8

15

24

41

57

93

163

247

322

412

0.01431

0.135

8

14

22

39

53

87

152

230

300

383

0.01539

0.140

7

13

21

36

49

81

142

214

279

357

0.01651

0.145

7

12

19

34

46

76

132

200

261

334

0.01767

0.150

6

11

18

31

43

71

124

187

244

312

0.01887

0.155

6

10

17

29

40

66

116

176

229

293

0.02011

0.160

5

10

16

28

38

62

109

165

216

276

0.02138

0.165

5

9

15

26

36

59

103

156

203

260

0.02270

0.170

5

9

14

25

34

56

97

147

192

245

0.02405

0.175

4

8

13

23

32

52

92

139

181

232

0.02545

0.180

4

8

13

22

30

50

87

131

171

219

0.02688

0.185

4

7

12

21

28

47

82

124

163

208

0.02835

0.190

4

7

11

20

27

45

78

118

154

197

0.02986

0.195

4

6

11

19

26

42

74

112

147

188

0.03142

0.200

3

6

10

18

24

40

71

107

140

178

0.03301

0.205

3

6

10

17

23

38

67

102

133

170

0.03464

0.210

3

6

9

16

22

37

64

97

127

162

0.03630

0.215

3

5

9

15

21

35

61

93

121

155

0.03801

0.220

3

5

8

15

20

33

59

89

116

148

0.03976

0.225

3

5

8

14

19

32

56

85

111

142

0.04155

0.230

3

5

8

13

18

31

54

81

106

136

0.04337

0.235

2

4

7

13

18

29

51

78

102

130

0.04524

0.240

2

4

7

12

17

28

49

75

98

125

0.04714

0.245

2

4

7

12

16

27

47

72

94

120

0.04909

0.250

2

4

6

11

16

26

46

69

90

115

0.05107

0.255

1

4

6

11

15

25

44

66

87

111

0.05309

0.260

1

4

6

11

14

24

42

64

83

107

0.05515

0.265

1

3

6

10

14

23

41

61

80

103

0.05726

0.270

1

3

6

10

13

22

39

59

77

99

0.05940

0.275

1

3

5

9

13

21

38

57

75

96

0.06158

0.280

1

3

5

9

12

21

36

55

72

92

0.06379

0.285

1

3

5

9

12

20

35

53

70

89

0.06605

0.290

1

3

5

8

12

19

34

51

67

86

0.06835

0.295

1

3

5

8

11

19

33

50

65

83

0.07069

0.300

1

3

4

8

11

18

32

48

63

80

0.07306

0.305

1

3

4

8

10

17

31

47

61

78

0.07548

0.310

1

2

4

7

10

17

30

45

59

75

0.07793

0.315

1

2

4

7

10

16

29

44

57

73

0.08042

0.320

1

2

4

7

10

16

28

42

55

71

0.08296

0.325

1

2

4

7

9

15

27

41

54

69

0.08553

0.330

1

2

4

6

9

15

26

40

52

67

0.08814

0.335

1

2

4

6

9

14

26

39

51

65

0.09079

0.340

1

1

3

6

8

14

25

38

49

63

0.09348

0.345

1

1

3

6

8

14

24

36

48

61

0.09621

0.350

1

1

3

6

8

13

23

35

46

59

0.09898

0.355

1

1

3

6

8

13

23

34

45

58

0.10179

0.360

1

1

3

5

7

13

22

34

44

56

0.10463

0.365

1

1

3

5

7

12

21

33

43

55

0.10752

0.370

1

1

3

5

7

12

21

32

42

53

0.11045

0.375

1

1

3

5

7

12

20

31

40

52

0.11341

0.380

1

1

3

5

7

11

20

30

39

50

0.11642

0.385

1

1

3

5

7

11

19

29

38

49

0.11946

0.390

1

1

3

5

6

11

19

29

37

48

0.12254

0.395

1

1

2

4

6

10

18

28

36

47

0.12566

0.400

1

1

2

4

6

10

18

27

36

46

0.12882

0.405

1

1

2

4

6

10

17

27

35

44

0.13203

0.410

1

1

2

4

6

10

17

26

34

43

0.13527

0.415

1

1

2

4

6

9

17

25

33

42

0.13854

0.420

1

1

2

4

5

9

16

25

32

41

0.14186

0.425

1

1

2

4

5

9

16

24

32

40

0.14522

0.430

1

1

2

4

5

9

15

24

31

39

0.14862

0.435

1

1

1

4

5

9

15

23

30

39

0.15205

0.440

1

1

1

4

5

8

15

22

29

38

0.15553

0.445

1

1

1

3

5

8

14

22

29

37

0.15904

0.450

1

1

1

3

5

8

14

21

28

36

0.16260

0.455

1

1

1

3

5

8

14

21

27

35

0.16619

0.460

1

1

1

3

4

8

13

21

27

34

0.16982

0.465

1

1

1

3

4

7

13

20

26

34

0.17349

0.470

1

1

1

3

4

7

13

20

26

33

0.17721

0.475

1

1

1

3

4

7

13

19

25

32

0.18096

0.480

1

1

1

3

4

7

12

19

25

32

0.18475

0.485

1

1

1

3

4

7

12

18

24

31

0.18857

0.490

1

1

1

3

4

7

12

18

24

30

0.19244

0.495

1

1

1

3

4

7

12

18

23

30

0.19635

0.500

1

1

1

3

4

6

11

17

23

29

0.20030

0.505

0

1

1

3

4

6

11

17

22

29

0.20428

0.510

0

1

1

3

4

6

11

17

22

28

0.20831

0.515

0

1

1

3

4

6

11

16

21

27

0.21237

0.520

0

1

1

2

3

6

11

16

21

27

0.21648

0.525

0

1

1

2

3

6

10

16

21

26

0.22062

0.530

0

1

1

2

3

6

10

15

20

26

0.22480

0.535

0

1

1

2

3

6

10

15

20

25

0.22902

0.540

0

1

1

2

3

5

10

15

19

25

0.23328

0.545

0

1

1

2

3

5

10

15

19

25

0.23758

0.550

0

1

1

2

3

5

9

14

19

24

0.24192

0.555

0

1

1

2

3

5

9

14

18

24

0.24630

0.560

0

1

1

2

3

5

9

14

18

23

0.25072

0.565

0

1

1

2

3

5

9

14

18

23

0.25518

0.570

0

1

1

1

3

5

9

13

17

22

0.25967

0.575

0

1

1

1

3

5

9

13

17

22

0.26421

0.580

0

1

1

1

3

5

8

13

17

22

0.26878

0.585

0

1

1

1

3

5

8

13

17

21

0.27340

0.590

0

1

1

1

3

5

8

12

16

21

0.27805

0.595

0

1

1

1

3

4

8

12

16

21

0.28274

0.600

0

1

1

1

3

4

8

12

16

20

0.28748

0.605

0

1

1

1

2

4

8

12

16

20

0.29225

0.610

0

1

1

1

2

4

8

12

15

20

0.29706

0.615

0

1

1

1

2

4

7

11

15

19

0.30191

0.620

0

1

1

1

2

4

7

11

15

19

0.30680

0.625

0

1

1

1

2

4

7

11

15

19

0.31172

0.630

0

1

1

1

2

4

7

11

14

18

0.31669

0.635

0

1

1

1

2

4

7

11

14

18

0.32170

0.640

0

1

1

1

2

4

7

11

14

18

0.32674

0.645

0

1

1

1

2

4

7

10

14

17

0.33183

0.650

0

1

1

1

2

4

7

10

13

17

0.33696

0.655

0

1

1

1

2

4

7

10

13

17

0.34212

0.660

0

1

1

1

2

4

6

10

13

17

0.34732

0.665

0

1

1

1

1

4

6

10

13

16

0.35256

0.670

0

0

1

1

1

3

6

10

13

16

0.35785

0.675

0

0

1

1

1

3

6

9

12

16

0.36317

0.680

0

0

1

1

1

3

6

9

12

16

0.36853

0.685

0

0

1

1

1

3

6

9

12

15

0.37393

0.690

0

0

1

1

1

3

6

9

12

15

0.37937

0.695

0

0

1

1

1

3

6

9

12

15

0.38484

0.700

0

0

1

1

1

3

6

9

12

15

0.39036

0.705

0

0

1

1

1

3

6

9

11

15

0.39592

0.710

0

0

1

1

1

3

6

9

11

14

0.40151

0.715

0

0

1

1

1

3

5

8

11

14

0.40715

0.720

0

0

1

1

1

3

5

8

11

14

0.41282

0.725

0

0

1

1

1

3

5

8

11

14

0.41854

0.730

0

0

1

1

1

3

5

8

11

14

0.42429

0.735

0

0

1

1

1

3

5

8

10

13

0.43008

0.740

0

0

1

1

1

3

5

8

10

13

0.43592

0.745

0

0

1

1

1

3

5

8

10

13

0.44179

0.750

0

0

1

1

1

3

5

8

10

13

0.44770

0.755

0

0

1

1

1

3

5

7

10

13

0.45365

0.760

0

0

1

1

1

3

5

7

10

13

0.45963

0.765

0

0

1

1

1

3

5

7

10

12

0.46566

0.770

0

0

1

1

1

3

5

7

9

12

0.47173

0.775

0

0

1

1

1

3

5

7

9

12

0.47784

0.780

0

0

1

1

1

2

5

7

9

12

0.48398

0.785

0

0

1

1

1

2

4

7

9

12

0.49017

0.790

0

0

1

1

1

2

4

7

9

12

0.49639

0.795

0

0

1

1

1

2

4

7

9

11

0.50265

0.800

0

0

1

1

1

2

4

7

9

11

0.50896

0.805

0

0

1

1

1

2

4

7

9

11

0.51530

0.810

0

0

1

1

1

2

4

6

9

11

0.52168

0.815

0

0

1

1

1

2

4

6

8

11

0.52810

0.820

0

0

1

1

1

2

4

6

8

11

0.53456

0.825

0

0

1

1

1

2

4

6

8

11

0.54106

0.830

0

0

1

1

1

2

4

6

8

10

0.54760

0.835

0

0

1

1

1

2

4

6

8

10

0.55418

0.840

0

0

1

1

1

2

4

6

8

10

0.56079

0.845

0

0

1

1

1

2

4

6

8

10

0.56745

0.850

0

0

0

1

1

2

4

6

8

10

0.57415

0.855

0

0

0

1

1

1

4

6

8

10

0.58088

0.860

0

0

0

1

1

1

4

6

8

10

0.58765

0.865

0

0

0

1

1

1

4

6

7

10

0.59447

0.870

0

0

0

1

1

1

4

6

7

10

0.60132

0.875

0

0

0

1

1

1

4

6

7

9

0.60821

0.880

0

0

0

1

1

1

4

5

7

9

0.61514

0.885

0

0

0

1

1

1

3

5

7

9

0.62211

0.890

0

0

0

1

1

1

3

5

7

9

0.62912

0.895

0

0

0

1

1

1

3

5

7

9

0.63617

0.900

0

0

0

1

1

1

3

5

7

9

0.64326

0.905

0

0

0

1

1

1

3

5

7

9

0.65039

0.910

0

0

0

1

1

1

3

5

7

9

0.65755

0.915

0

0

0

1

1

1

3

5

7

9

0.66476

0.920

0

0

0

1

1

1

3

5

7

8

0.67201

0.925

0

0

0

1

1

1

3

5

6

8

0.67929

0.930

0

0

0

1

1

1

3

5

6

8

0.68661

0.935

0

0

0

1

1

1

3

5

6

8

0.69398

0.940

0

0

0

1

1

1

3

5

6

8

0.70138

0.945

0

0

0

1

1

1

3

5

6

8

0.70882

0.950

0

0

0

1

1

1

3

5

6

8

0.71630

0.955

0

0

0

1

1

1

3

5

6

8

0.72382

0.960

0

0

0

1

1

1

3

5

6

8

0.73138

0.965

0

0

0

1

1

1

3

4

6

8

0.73898

0.970

0

0

0

1

1

1

3

4

6

8

0.74662

0.975

0

0

0

1

1

1

3

4

6

8

0.75430

0.980

0

0

0

1

1

1

3

4

6

7

0.76201

0.985

0

0

0

1

1

1

3

4

6

7

0.76977

0.990

0

0

0

1

1

1

3

4

6

7

0.77756

0.995

0

0

0

1

1

1

3

4

6

7

0.78540

1.000