Enter your current (amps), one-way wire length, allowable voltage drop, and electrical system type to find the correct wire cross-sectional area for your 24V system. The calculator returns the required wire area in mm², the closest AWG gauge, and the actual voltage drop percentage — helping you avoid undersized cables that waste power or create fire hazards.
Required Wire Area
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Recommended AWG Gauge
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Voltage Drop
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Wire Resistance
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Power Loss in Wire
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A typical 24V trolling motor draws 40–60 amps. For a 5-meter run at 40A with a 3% voltage drop, you'd need roughly 14–20 mm² of wire area — corresponding to about 6 AWG copper cable. Always calculate based on your actual current draw and cable run length using the calculator above.
Voltage drop is the reduction in voltage from the source to the load due to wire resistance. The NEC (National Electrical Code) recommends a maximum of 3% for branch circuits and 5% total including feeder circuits. For sensitive electronics or long runs, keep it at or below 3% for best performance.
For DC and single-phase AC: A = (I × ρ × 2 × L) / ΔV, where A is cross-sectional area in m², I is current in amps, ρ is resistivity of the conductor (1.72×10⁻⁸ Ω·m for copper), L is one-way wire length in meters, and ΔV is the allowable voltage drop in volts. For three-phase systems, the factor 2 is replaced by √3.
Yes. As wire temperature increases, copper resistivity increases, which raises resistance and voltage drop. The standard resistivity value of copper (1.72×10⁻⁸ Ω·m) applies at 20°C. In high-temperature environments, you may need to upsize the wire. Always check conductor ampacity ratings for the ambient temperature of your installation.
AWG (American Wire Gauge) is a standardized US system where lower numbers indicate thicker wire (e.g., 4 AWG is thicker than 12 AWG). The metric system uses cross-sectional area in mm², which is more common in Europe and internationally. The calculator converts between both so you can buy the right wire regardless of the standard used in your region.
Undersized wire has higher resistance, which causes excessive heat buildup during current flow. This can damage insulation, degrade performance, and in worst cases lead to electrical fires. It also causes significant voltage drop, meaning your devices receive less voltage than required and may malfunction or become inefficient.
Copper is generally preferred for 24V low-voltage systems because it has lower resistivity, better conductivity, and is easier to work with in smaller gauges. Aluminum is lighter and cheaper for large power runs but requires larger cross-sections for the same current capacity and needs special connectors to prevent corrosion at termination points.
It depends on the current and panel-to-battery distance. For a typical 24V solar setup producing 20–30A over a 5-meter run, 6–8 AWG (8–10 mm²) copper wire is common. Use the calculator with your specific current and cable length to get the precise minimum wire size and the recommended standard AWG size.