Current | Phases | Wiring system | Overhead lines | Cables |
DC |
| 2 w | 1 | 1 |
2 w, earthed midpoint | 1/4 | 1 | ||
3 w | 0.3125 | 1.25 | ||
AC | 1 | 2 w | 2/cos2ϕ | 2/cos2ϕ |
2 w, earthed midpoint | 0.5/cos2ϕ | 2/cos ϕ | ||
3w | 0.625/cos2ϕ | 2.5/cos2ϕ | ||
2 | 4 w | 0.5/cos2ϕ | 2/cos2ϕ | |
3 w | 1.457/cos2ϕ | 2.914/cos2ϕ | ||
3 | 3 w | 0.5/cos2ϕ | 1.5/cos2ϕ | |
4 w | 0.583/cos2ϕ | 1.75/cos2ϕ |