Table 17. Comparison of flat bar d.c. current ratings for different ambient and working temperatures

a. Ambient temp = 30°C

Calculated from formula 1, section 3

Temp. coeff. of resistance, a, at 30°C = 3.781 x 10–3

Temp. coeff. of resistivity, b, at 30°C = 3.794 x 10–3

Resistivity, r, at 30°C = 1.772mW.cm

Size Temp rise (°C)
mm 10 20 30 40 50 60
12.5 x 2.5 65 95 120 145 160 175
16 x 2.5 80 120 150 175 200 215
20 x 2.5 95 145 180 210 240 260
25 x 2.5 115 175 220 255 290 315
31.5 x 2.5 140 210 265 310 350 385
40 x 2.5 175 260 325 385 430 475
50 x 2.5 210 315 395 465 525 575
63 x 2.5 255 385 485 570 640 705
16 x 4 105 155 195 230 260 285
20 x 4 125 185 235 275 310 340
25 x 4 150 225 280 330 370 410
31.5 x 4 180 270 340 400 450 500
40 x 4 220 335 420 490 555 610
50 x 4 270 405 510 595 670 740
63 x 4 330 495 620 725 820 900
80 x 4 405 605 765 895 1010 1110
100 x 4 490 735 925 1085 1225 1350
25 x 6.3 195 290 365 425 480 530
31.5 x 6.3 235 350 440 515 580 640
40 x 6.3 285 425 535 630 710 780
50 x 6.3 345 515 650 760 855 940
63 x 6.3 420 625 790 925 1040 1145
80 x 6.3 515 770 970 1135 1280 1405
100 x 6.3 620 930 1175 1375 1550 1705
125 x 63 755 1130 1425 1670 1885 2070
160 x 6.3 935 1405 1770 2070 2335 2570
50 x 10 445 665 835 980 1105 1215
63 x 10 535 805 1015 1190 1340 1475
80 x 10 655 985 1240 1455 1640 1800
100 x 10 795 1190 1500 1755 1980 2180
125 x 10 960 1440 1815 2125 2400 2640
160 x 10 1190 1785 2245 2635 2970 3265
200 x 10 1445 2165 2725 3195 3605 3965
250 x 10 1755 2635 3315 3885 4380 4820
100 x 16 1025 1535 1935 2270 2555 2815
125 x 16 1235 1855 2335 2735 3085 3395
160 x 16 1525 2290 2880 3375 3805 4185
200 x 16 1850 2770 3490 4090 4610 5070
250 x 16 2240 3360 4230 4955 5590 6150
315 x 16 2740 4105 5170 6060 6830 7515

 

b. Ambient temp = 40°C

Calculated from formula 1, Section 3

Temp. coeff. of resistance, a, at 40°C = 3.644 x 10–3

Temp. coeff. of resistivity, b, at 40°C = 3.656 x 10–3

Resistivity, r, at 40°C = 1.833 mW.cm

Size

Temp rise (°C)
mm 10 20 30 40 50 60
12.5 x 2.5 65 95 120 140 160 175
16 x 2.5 80 115 145 175 195 215
20 x 2.5 95 140 180 210 235 260
25 x 2.5 115 170 215 250 285 315
31.5 x 2.5 140 210 260 305 345 380
40 x 2.5 170 255 320 380 425 470
50 x 2.5 205 310 390 460 515 570
63 x 2.5 255 380 480 560 635 695
16 x 4 100 155 190 225 255 280
20 x 4 120 185 230 270 305 335
25 x 4 145 220 280 325 365 405
31.5 x 4 180 270 335 395 445 490
40 x 4 220 330 415 485 545 600
50 x 4 265 395 500 585 660 730
63 x 4 325 485 610 715 810 890
80 x 4 400 595 750 880 995 1095
100 x 4 485 725 915 1070 1210 1330
25 x 6.3 190 285 360 420 475 525
31.5 x 6.3 230 345 435 510 575 630
40 x 6.3 280 420 530 620 700 770
50 x 6.3 340 505 640 750 845 930
63 x 6.3 410 615 775 910 1030 1130
80 x 6.3 505 755 955 1122 1260 1390
100 x 6.3 610 920 1155 1355 1530 1685
125 x 6.3 745 1115 1405 1645 1855 2045
160 x 6.3 920 1385 1740 2040 2305 2535
50 x 10 435 655 825 965 1090 1200
63 x 10 530 795 1000 1170 1320 1455
80 x 10 645 970 1220 1430 1615 1780
100 x 10 780 1170 1475 1730 1955 2150
125 x 10 945 1420 1790 2095 2365 2605
160 x 10 1170 1755 2215 2595 2930 3225
200 x 10 1420 2135 2685 3150 3555 3915
250 x 10 1730 2595 3265 3830 4320 4755
100 x 16 1010 1515 1905 2235 2520 2775
125 x 16 1220 1825 2300 2700 3045 3350
160 x 16 1500 2255 2840 3330 3755 4130
200 x 16 1820 2730 3435 4030 4545 5005
250 x 16 2205 3310 4165 4885 5510 6070
315 x 16 2695 4045 5095 5975 6740 7415

 

c. Ambient temp = 50°C

Calculated from formula 1, Section 3

Temp. coeff. of resistance, a, at 50°C = 3.516 x 10–3

Temp. coeff. of resistivity, b, at 50°C = 3.527 x 10–3

Resistivity, , at 50°C = 1.888 .cm

Size

Temp rise (°C)
mm 10 20 30 40 50 60
12.5 x 2.5 65 95 120 140 155 175
16 x 2.5 75 115 145 170 195 210
20 x 2.5 95 140 175 205 230 255
25 x 2.5 110 170 210 250 280 310
31.5 x 2.5 135 205 260 305 340 375
40 x 2.5 170 250 320 375 420 465
50 x 2.5 205 305 385 455 510 565
63 x 2.5 250 375 470 555 625 690
16 x 4 100 150 190 220 250 275
20 x 4 120 180 230 265 300 330
25 x 4 145 215 275 320 365 400
31.5 x 4 175 265 335 390 440 485
40 x 4 215 325 410 480 540 595
50 x 4 260 390 495 580 655 720
63 x 4 320 480 605 705 800 880
80 x 4 390 590 740 870 980 1080
100 x 4 475 715 900 1060 1185 1315
25 x 6.3 185 280 355 415 470 515
31.5 x 6.3 225 340 430 500 565 625
40 x 6.3 275 415 520 610 690 760
50 x 6.3 335 500 630 740 835 920
63 x 6.3 405 610 765 900 1015 1120
80 x 6.3 500 745 940 1105 1245 1370
100 x 6.3 605 905 1140 1340 1510 1665
125 x 6.3 730 1100 1385 1625 1835 2020
160 x 6.3 910 1365 1720 2015 2275 2505
50 x 10 430 645 815 955 1075 1185
63 x 10 520 780 985 1155 1305 1435
80 x 10 635 955 1205 1415 1595 1755
100 x 10 770 1155 1455 1710 1930 2125
125 x 10 935 1400 1765 2070 2335 2575
160 x 10 1155 1735 2185 2565 2890 3185
200 x 10 1400 2105 2650 3110 3510 3865
250 x 10 1705 2555 3220 3780 4265 4700
100 x 16 995 1495 1880 2210 2490 2745
125 x 16 1200 1800 2270 2665 3005 3310
160 x 16 1480 2220 2800 3285 3710 4085
200 x 16 1795 2690 3390 3980 4490 4945
250 x 16 2175 3265 4110 4825 5445 5995
315 x 16 2660 3990 5025 5900 6655 7330