$U_n$ is the rated line-to-line voltage of the cable. $U_m$ is the highest voltage for the equipment and $U_0$ is the test voltage (values from the standards listed below).
The rated voltage of a cable is limited to the choices below. However, when laid in a project, the operating voltage of every cable system can be chosen arbitrary in the range between 400 V to 500 kV AC (1 to 5 kV DC).
$U_n$ | $U_m$ | $U_0$ | Standard |
---|---|---|---|
208 V | 240 V | 120 V | USA, Canada |
400 V | 440 V | 230 V | DIN VDE 0298-3 |
480 V | 600 V | 277 V | USA, Canada |
500 V | 550 V | 300 V | DIN VDE 0298-3 |
750 V | 825 V | 450 V | DIN VDE 0298-3 |
1 kV | 1.2 kV | 0.6 kV | IEC 60502-1 Ed.2.1 |
3 kV | 3.6 kV | 1.8 kV | IEC 60502-1 Ed.2.1 |
6 kV | 7.2 kV | 3.6 kV | IEC 60502-2 Ed.3.0 |
6.6 kV | 7.2 kV | 3.8 kV | HD 620 S2:2010 Part 1 |
10 kV | 12 kV | 6 kV | IEC 60502-2 Ed.3.0 |
11 kV | 12 kV | 6.35 kV | UK & Commonwealth |
15 kV | 17.5 kV | 8.7 kV | IEC 60502-2 Ed.3.0 |
20 kV | 24 kV | 12 kV | IEC 60502-2 Ed.3.0 |
22 kV | 24 kV | 12.7 kV | HD 620 S2:2010 Part 1 |
25 kV | 30 kV | 15 kV | HD 620 S2:2010 Part 1 |
30 kV | 36 kV | 18 kV | IEC 60502-2 Ed.3.0 |
33 kV | 36 kV | 19 kV | UK & Commonwealth |
36 kV | 42 kV | 20.8 kV | HD 620 S2:2010 Part 1 |
45 kV | 52 kV | 26 kV | IEC 60840 Ed.5.0 |
60 kV | 72.5 kV | 36 kV | IEC 60840 Ed.4.0 |
66 kV | 72.5 kV | 38 kV | UK & Commonwealth |
110 kV | 123 kV | 64 kV | IEC 60840 Ed.5.0 |
132 kV | 145 kV | 76 kV | IEC 60840 Ed.5.0 |
150 kV | 170 kV | 87 kV | IEC 60840 Ed.5.0 |
220 kV | 245 kV | 127 kV | IEC 62067 Ed.3.0 |
275 kV | 300 kV | 160 kV | UK & Commonwealth |
280 kV | 300 kV | 160 kV | IEC 62067 Ed.3.0 |
330 kV | 362 kV | 190 kV | IEC 62067 Ed.3.0 |
380 kV | 420 kV | 220 kV | IEC 62067 Ed.3.0 |
400 kV | 420 kV | 230 kV | UK & Commonwealth |
500 kV | 550 kV | 290 kV | IEC 62067 Ed.3.0 |