NEC 310-16 Allowable Ampacities of Insulated Conductors B

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NEC 310-16 Allowable Ampacities of Insulated Conductors

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Table 310.16 Allowable Ampacities of Insulated Conductors Rated 0 Through 2000 Volts, 60¡ãC Through 90¡ãC (140¡ãF Through 194¡ãF), Not More Than

Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried), Based on Ambient Temperature of 30¡ãC (86¡ãF)

Temperature Rating of Conductor (See Table 310.13.)

60¡ãC ¨C (140¡ãF)

Types TW,

UF

Size AWG or kcmil

75¡ãC ¨C (167¡ãF)

90¡ãC ¨C (194¡ãF)

Types RHW,

THHW, THW,

THWN, XHHW,

USE, ZW

Types TBS, SA, SIS,

FEP, FEPB, MI, RHH,

RHW-2, THHN,

THHW, THW-2,

THWN-2, USE-2, XHH,

XHHW, XHHW-2,

ZW-2

60¡ãC ¨C (140¡ãF)

Types TW,

UF

COPPER

75¡ãC ¨C (167¡ãF)

90¡ãC ¨C (194¡ãF)

Types RHW,

THHW, THW,

THWN, XHHW,

USE

Types TBS, SA, SIS,

THHN, THHW,

THW-2, THWN-2,

RHH, RHW-2, USE-2,

XHH, XHHW,

XHHW-2, ZW-2

ALUMINUM OR COPPER-CLAD ALUMINUM

Size AWG or kcmil

18

16

14*

12*

10*

¡ª

¡ª

20

25

30

¡ª

¡ª

20

25

35

14

18

25

30

40

¡ª

¡ª

¡ª

20

25

¡ª

¡ª

¡ª

20

30

¡ª

¡ª

¡ª

25

35

¡ª

¡ª

¡ª

12*

10*

8

6

4

3

2

1

40

55

70

85

95

110

50

65

85

100

115

130

55

75

95

110

130

150

30

40

55

65

75

85

40

50

65

75

90

100

45

60

75

85

100

115

8

6

4

3

2

1

1/0

2/0

3/0

4/0

125

145

165

195

150

175

200

230

170

195

225

260

100

115

130

150

120

135

155

180

135

150

175

205

1/0

2/0

3/0

4/0

250

300

350

400

500

215

240

260

280

320

255

285

310

335

380

290

320

350

380

430

170

190

210

225

260

205

230

250

270

310

230

255

280

305

350

250

300

350

400

500

600

700

750

800

900

355

385

400

410

435

420

460

475

490

520

475

520

535

555

585

285

310

320

330

355

340

375

385

395

425

385

420

435

450

480

600

700

750

800

900

1000

1250

1500

1750

2000

455

495

520

545

560

545

590

625

650

665

615

665

705

735

750

375

405

435

455

470

445

485

520

545

560

500

545

585

615

630

1000

1250

1500

1750

2000

CORRECTION FACTORS

Ambient

Temp.(¡ãC)

For ambient temperatures other than 30¡ãC (86¡ãF),

multiply the allowable ampacities shown above by the appropriate factor shown below.

Ambient

Temp. (¡ãF)

21¨C25

1.08

1.05

1.04

1.08

1.05

1.04

70¨C77

26¨C30

1.00

1.00

1.00

1.00

1.00

1.00

78¨C86

31¨C35

0.91

0.94

0.96

0.91

0.94

0.96

87¨C95

36¨C40

0.82

0.88

0.91

0.82

0.88

0.91

96¨C104

41¨C45

0.71

0.82

0.87

0.71

0.82

0.87

105¨C113

46¨C50

0.58

0.75

0.82

0.58

0.75

0.82

114¨C122

51¨C55

0.41

0.67

0.76

0.41

0.67

0.76

123¨C131

56¨C60

¡ª

0.58

0.71

¡ª

0.58

0.71

132¨C140

61¨C70

¡ª

0.33

0.58

¡ª

0.33

0.58

141¨C158

71¨C80

¡ª

¡ª

0.41

¡ª

¡ª

0.41

159¨C176

*See 240.4(D).

Reprinted with permission from NFPA 70-1999, National Electrical Code ?, Copyright ? 1998, National Fire Protection Association, Quincy, MA 02269. This

reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.

National Electrical Code and NEC are registered trademarks of the National Fire Protection Association, Quincy, MA.

? 2002 Thomas & Betts Corporation. Specifications are subject to change without notice.



B35

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Article 310 ¨C Conductors for General Wiring

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