Voltage Drop for 10 AWG, 20 m, 20 A
Calculate the voltage drop along a 10 AWG wire run of 20 meters carrying 20 amperes for a sub-panel or EV charger feed.
How to use this tool
- Enter wire gauge (awg), one-way wire length and current in the fields above.
- Results update instantly as you type โ or click Calculate.
- Read your voltage drop and the full breakdown beneath it.
10 AWG at 20 m and 20 A is typical for EV charger circuits and workshop sub-panel feeds where voltage drop compliance is critical.
Frequently asked questions
- What is the maximum recommended voltage drop?
- The NEC recommends no more than 3% voltage drop on a branch circuit and no more than 5% combined (feeder + branch). Above 3% you may notice dimmer lights or reduced motor torque.
- Does the return conductor also contribute?
- Yes โ current flows through both the hot and neutral (or ground-return) conductors, so the effective resistance is twice the one-way value.