Electrical

Wire Gauge Calculator

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Circuit Voltage

Load CurrentMaximum current flow expected from the load.

Wire Length (one-way)Distance from the power source to the load. The calculator doubles this for the full round-trip wire length.

Distance from source to load

Max Voltage DropThe loss of energy as current moves through a wire results in voltage drop. A larger wire has less resistance and minimizes drop.

Fuse / Breaker

I don't know — recommend one for meI already have a fuse:

Derating FactorsFactors that reduce the wire's effective ampacity or increase the required size.

Ambient temperature of 50°C (122°F) or more Equivalent to "In Engine Room" per ABYC standards. Reduces wire ampacity by 15%, since wires in hot areas (ceiling, walls) have less capacity to dissipate the heat generated by current flow.Load runs continuously for 20 minutes or more Increases the load current by 25% for voltage drop calculation (not for fuse sizing). This accounts for the extra heat that builds up when current flows continuously.Wire in conduit, insulation sleeve, or bundled with 2+ other wires Wire ampacity is reduced by 30%, since its ability to dissipate heat generated by current flow is reduced.

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Enter a load current and wire length to see results.