What cable gauge avoids voltage drop?
The right wire gauge for your solar or 12 V setup, and what an undersized cable really costs you.
⚡ Your circuit
A cable that's too thin over a long run drops the voltage before it even reaches the battery: less charging current, and sometimes a controller that cuts out. Pick a panel from our catalogue or enter your own values.
Voltage drop
0.9 %
ideal
Voltage drop
-0.46 V
Voltage at the far end
47.54 V
Recommended minimum gauge
14 AWG
Direct-current calculation, cable there-and-back, copper resistivity at operating temperature (0.0225 Ω·mm²/m at 70 °C, converted here to standard AWG cross-sections). By default, picking a panel sets the current to its Isc (short-circuit current), the most conservative sizing value. As a rule of thumb, keep drop at or under 3% on a branch circuit, matching the widely used NEC voltage-drop recommendation.
Voltage drop by wire gauge, for this current and length
| Gauge | Drop | Voltage at end | Verdict |
|---|---|---|---|
| 14 AWG | 2.4 % | 46.85 V | ideal |
| 12 AWG | 1.5 % | 47.28 V | ideal |
| 10 AWG | 0.9 % | 47.54 V | ideal |
| 8 AWG | 0.6 % | 47.71 V | ideal |
| 6 AWG | 0.4 % | 47.82 V | ideal |
| 4 AWG | 0.2 % | 47.89 V | ideal |
| 2 AWG | 0.1 % | 47.93 V | ideal |
| 1 AWG | 0.1 % | 47.94 V | ideal |
| 1/0 AWG | 0.1 % | 47.96 V | ideal |