"Voltage Drop Index" method
of determining
wire size needed
| Amps x Distance (one way) |
= VDI |
| Voltage x Percent Loss |
| VDI | Gauge | |
| 1 | = | #16 |
| 2 | = | #14 |
| 3 | = | #12 |
| 5 | = | #10 |
| 8 | = | #8 |
| 12 | = | #6 |
| 20 | = | #4 |
| 34 | = | #2 |
| 49 | = | 1/0 |
| 62 | = | 2/0 |
| 78 | = | 3/0 |
| 99 | = | 4/0 |
For example,
10 Amps Current
100 Fee one-way distance
24 Volt system
2% Loss
Calculate,
10 x 100 = 20.83
24 x 2
Use #4 Wire
