| IEC 71-1, 1993-12 Insulation coordination Part 1: definitions, principles and rules. Range 1: 1 kV < Um ≤ 245 kV | |||||
| Highest voltage for equipment (Um) | Standard short-duration power frequency withstand voltage | Standard lightning impulse withstand voltage | |||
| IEEE 1313.1-1996 Insulation coordination―definitions, principles and rules. Class 1: 15 kV < Um ≤ 245 kV | |||||
| Maximum system voltage (phase-to-phase) Vm | Low-frequency, short-duration withstand voltage (phase-to-ground) | Basic lightning impulse insulation level (phase-to-phase) BIL | |||
| kV, rms value | kV, rms value | kV, crest value | |||
| IEC | IEEE | IEC | IEEE | IEC | IEEE |
| 3.6 |
| 10 |
| 20, 40 |
|
| 7.2 | 20 | 40, 60 | |||
| 12 | 28 | 60, 75, 95 | |||
| 17.5 | 15 | 38 | 34 | 75, 95 | 95, 100 |
| 24 | 26.2 | 50 | 50 | 95, 125, 145 | 150 |
| 36 | 36.2 | 70 | 70 | 145, 170 | 200 |
| 52 | 48.3 | 95 | 95 | 250 | 250 |
| 72.5 | 72.5 | 140 | 95 140 | 325 | 250 350 |