Wire Gauge Calculator
Enter your circuit’s amp draw, wire run length, and system voltage to get the correct wire gauge (AWG) for a safe, low-voltage-drop connection.
Recommended Wire Gauge
4 AWG
For 40A over a 20-ft round-trip run at 3% max voltage drop
This is a sizing estimate using the standard voltage-drop formula for copper wire. Always verify against your wire manufacturer’s ampacity chart, and remember: your fuse should be sized to the wire’s safe ampacity, not just the appliance’s draw.
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