Annex B Application Information for Ampacity Calculation
Annex B Application Information for Ampacity Calculation
Annex B Application Information for Ampacity Calculation
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ANNEX B<strong>Annex</strong> B: AmpacitiesTable B.310.5 Ampacities of Single Insulated Conductors, Rated 0 through 2000 Volts, inNonmagnetic Underground Electrical Ducts (One Conductor per Electrical Duct),Based on Ambient Earth Temperature of 20°C (68°F), Electrical Duct Arrangementper Figure B.310.2, Conductor Temperature 7SoC (167°F)Size(kcmil)3 Electrical Ducts(Fig. B.310.2,Detail 2)Types RHW,THHW,THW,THWN,XHHW,USE6 Electrical Ducts 9 Electrical Ducts 3 Electrical Ducts 6 Electrical Ducts 9 Electrical Ducts(Fig. B.310.2, (Fig. B.310.2, (Fig. B.310.2, (Fig. B.310.2, (Fig. B.310.2,Detail 3) Detail 4) Detail 2) Detail 3) Detail 4)Types RHW, Types RHW, Types RHW, Types RHW, Types RHW,THHW,THW, THHW,THW, THHW,THW, THHW,THW, THHW,THW,THWN,XHHW, THWN,XHHW, THWN,XHHW, THWN,XHHW, THWN,XHHW,USE USE USE USE USESizeCOPPER ALUMINUM OR COPPER·CLAD ALUMINUM (kcmil)RHO RHO RHO60 90 120LF LF LF50 100 100250 410 344 327350 503 418 396500 624 511 484750 794 640 6031000 936 745 7001250 1055 832 7811500 1160 907 8491750 1250 970 9072000 1332 1027 959RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO60 90 120 60 90 120 60 90 120 60 90 120 60 90 120LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF50 100 100 50 100 100 50 100 100 50 100 100 50 100 100386 295 275 369 270 252 320 269 256 302 230 214 288 211 197 250472 355 330 446 322 299 393 327 310 369 277 258 350 252 235 350583 431 400 545 387 360 489 401 379 457 337 313 430 305 284 500736 534 494 674 469 434 626 505 475 581 421 389 538 375 347 750864 617 570 776 533 493 744 593 557 687 491 453 629 432 399 1000970 686 632 854 581 536 848 668 627 I 779 551 508 703 478 441 12501063 744 685 918 619 571 941 736 689 863 604 556 767 517 477 15001142 793 729 975 651 599 1026 796 745 I 937 651 598 823 550 507 17501213 836 768 1030 683 628 1103 850 794 1005 693 636 877 581 535 2000AmbientTemp.(0C)Correction FactorsAmbientTemp.(OF)6-10 1.0911-15 1.0416-20 1.0021-25 0.9526-30 0.901.09 1.091.09 1.09 1.09 43-501.041.04 1.041.04 1.04 52-591.00 1.00 1.00 1.001.00 61~80.95 0.95 0.950.95 0.95 70-77I 0.90 0.90 0.900.900.90 79-86i2008 Edition NATIONAL ELECTRICAL CODE 70-693
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