The following table can be used to determine the force between two busses during a short circuit condition.
Find the short circuit current in the first column and then find the distance between conductors at the top
of the chart. The distance is given in inches. The short circuit current is given in amps.
The resultant force in the chart is given in pounds per foot. This chart is base on the formula:
FORCE = (43.2 * SSA * SSA * 1x10-7)/D
where:
SSA = short circuit amps
D = distance between centers of conductors.
| SSA | 12" | 15" | 18" | 21" | 24" | 27" | 30" | 33" | 36" | 40" | 50" | 60" | 70" | 80" |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2000 | 1.4 | 1.2 | 1.0 | 0.8 | 0.7 | 0.6 | 0.6 | 0.5 | 0.5 | 0.4 | 0.3 | 0.3 | 0.2 | 0.2 |
| 2500 | 2.3 | 1.8 | 1.5 | 1.3 | 1.1 | 1.0 | 0.9 | 0.8 | 0.8 | 0.7 | 0.5 | 0.5 | 0.4 | 0.3 |
| 3000 | 3.2 | 2.6 | 2.2 | 1.9 | 1.6 | 1.4 | 1.3 | 1.2 | 1.1 | 1.0 | 0.8 | 0.6 | 0.6 | 0.5 |
| 4000 | 5.8 | 4.6 | 3.8 | 3.3 | 2.9 | 2.6 | 2.3 | 2.1 | 1.9 | 1.7 | 1.4 | 1.2 | 1.0 | 0.9 |
| 5000 | 9.0 | 7.2 | 6.0 | 5.1 | 4.5 | 4.0 | 3.6 | 3.3 | 3.0 | 2.7 | 2.2 | 1.8 | 1.5 | 1.4 |
| 6000 | 13.0 | 10.4 | 8.6 | 7.4 | 6.5 | 5.8 | 5.2 | 4.7 | 4.3 | 3.9 | 3.1 | 2.6 | 2.2 | 1.9 |
| 7000 | 17.6 | 14.1 | 11.8 | 10.1 | 8.8 | 7.8 | 7.1 | 6.4 | 5.9 | 5.3 | 4.2 | 3.5 | 3.0 | 2.6 |
| 8000 | 23.0 | 18.4 | 15.4 | 13.2 | 11.5 | 10.2 | 9.2 | 8.4 | 7.7 | 6.9 | 5.5 | 4.6 | 3.9 | 3.5 |
| 9000 | 29.2 | 23.3 | 19.4 | 16.7 | 14.6 | 13.0 | 11.7 | 10.6 | 9.7 | 8.7 | 7.0 | 5.8 | 5.0 | 4.4 |
| 10000 | 36.0 | 28.8 | 24.0 | 20.6 | 18.0 | 16.0 | 14.4 | 13.1 | 12.0 | 10.8 | 8.6 | 7.2 | 6.2 | 5.4 |
| 12000 | 51.8 | 41.5 | 34.6 | 29.6 | 25.9 | 23.0 | 20.7 | 18.9 | 17.3 | 15.6 | 12.4 | 10.4 | 8.9 | 7.8 |
| 15000 | 81.0 | 64.8 | 54.0 | 46.3 | 40.5 | 36.0 | 32.4 | 29.5 | 27.0 | 24.3 | 19.4 | 16.2 | 13.9 | 12.2 |
| 20000 | 144.0 | 115.2 | 96.0 | 82.3 | 72.0 | 64.0 | 57.6 | 52.4 | 48.0 | 43.2 | 34.6 | 28.8 | 24.7 | 21.6 |
| 25000 | 225.0 | 180.0 | 150.0 | 128.6 | 112.5 | 100.0 | 90.0 | 81.8 | 75.0 | 67.5 | 54.0 | 45.0 | 38.6 | 33.8 |
| 30000 | 324.0 | 259.2 | 216.0 | 185.1 | 162.0 | 144.0 | 129.6 | 117.8 | 108.0 | 97.2 | 77.8 | 64.8 | 55.5 | 48.6 |
| 35000 | 441.0 | 352.8 | 294.0 | 252.0 | 220.5 | 196.0 | 176.4 | 160.4 | 147.0 | 132.3 | 105.8 | 88.2 | 75.6 | 66.2 |
| 40000 | 576.0 | 460.8 | 384.0 | 329.1 | 288.0 | 256.0 | 230.4 | 209.5 | 192.0 | 172.8 | 138.2 | 115.2 | 98.7 | 86.4 |
| 45000 | 729.0 | 583.2 | 486.0 | 416.6 | 364.5 | 324.0 | 291.6 | 265.1 | 243.0 | 218.7 | 175.0 | 145.8 | 125.0 | 109.4 |
| 50000 | 900.0 | 720.0 | 600.0 | 514.3 | 450.0 | 400.0 | 360.0 | 327.3 | 300.0 | 270.0 | 216.0 | 180.0 | 154.3 | 135.0 |
| 60000 | 1296.0 | 1036.8 | 864.0 | 740.6 | 648.0 | 576.0 | 518.4 | 471.3 | 432.0 | 388.8 | 311.0 | 259.2 | 222.2 | 194.4 |
| 70000 | 1764.0 | 1411.2 | 1176.0 | 1008.0 | 882.0 | 784.0 | 705.6 | 641.5 | 588.0 | 529.2 | 423.4 | 352.8 | 302.4 | 264.6 |
| 80000 | 2304.0 | 1843.2 | 1536.0 | 1316.6 | 1152.0 | 1024.0 | 921.6 | 837.8 | 768.0 | 691.2 | 553.0 | 460.8 | 395.0 | 345.6 |
| 90000 | 2916.0 | 2332.8 | 1944.0 | 1666.3 | 1458.0 | 1296.0 | 1166.4 | 1060.4 | 972.0 | 874.8 | 699.8 | 583.2 | 499.9 | 437.4 |
| 100000 | 3600.0 | 2880.0 | 2400.0 | 2057.1 | 1800.0 | 1600.0 | 1440.0 | 1309.1 | 1200.0 | 1080.0 | 864.0 | 720.0 | 617.1 | 540.0 |