En 
SvCable sizing guide
Is there a standard?
Here are some examples that show how you can size your cable for different situations. It is important to take both the current and the voltage drop into account when choosing a suitable cable size. If you want a more precise sizing, or if you are unsure how to proceed, you can use our customized calculator.
Type of cable
The charging circuit
Generator 50 A to the battery bank. Between the batteries, a smaller‑gauge cable can be used.
Calculated based on a maximum voltage drop of 0.1 V.
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 1.5 | 3 | 35 |
| 2.5 | 5 | 50 |
| 3.5 | 7 | 70 |
| 4.5 | 9 | 95 |
| 5.5 | 11 | 120 |
Bow thruster or anchor winch
Between bow propeller/ anchor winch and battery. This also applies to larger starter motors. 3.5hp = 2500 w ≈ 250 A.
Calculated on max 1V voltage drop
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 2.5 | 5 | 25 |
| 3.5 | 7 | 35 |
| 4.5 | 9 | 50 |
| 5.5 | 11 | 70 |
| 6.5 | 13 | 95 |
| 7.5 | 15 | 120 |
Bow thruster 7 hp
Between bogpropeller and battery. 7 hp ≈ 5000 W ≈ 500 A
Calculated on max 1V voltage drop
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 2.5 | 5 | 50 |
| 3.5 | 7 | 70 |
| 4.5 | 9 | 95 |
| 5.5 | 11 | 120 |
| 7 | 14 | 2 x 70 |
| 9 | 18 | 2 x 95 |
| 11 | 22 | 2 x 120 |
Lantern in mast
25 W = 2 A
Calculated on max 0.5V voltage drop
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 18 | 36 | 2,5 |
| 20 | 40 | 4 |
| 25 | 50 | 4 |
Supply to the electricity centre
Between battery and switchboard.
500 W = 50 A
Calculated on max 1V voltage drop
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 2.5 | 5 | 10 |
| 3.5 | 7 | 16 |
| 4.5 | 9 | 25 |
| 5.5 | 11 | 25 |
| 6.5 | 13 | 25 |
| 7.5 | 15 | 35 |
| 8.5 | 17 | 35 |
Solar panel or charger
50 W = 4 A
Calculated on max 0.1V voltage drop
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 2.5 | 5 | 4 |
| 3.5 | 7 | 6 |
| 4.5 | 9 | 10 |
| 5.5 | 11 | 10 |
| 6.5 | 13 | 10 |
| 7.5 | 15 | 10 |
| 8.5 | 17 | 16 |
Fridge or heater
60 W = 5 A
Calculated on max 0.1V voltage drop
| Distance (m) | Total cable length (m) | Cable area (mm²) |
|---|---|---|
| 2.5 | 5 | 6 |
| 3.5 | 7 | 6 |
| 4.5 | 9 | 10 |
| 5.5 | 11 | 10 |
| 6.5 | 13 | 10 |
| 7.5 | 15 | 10 |