Wire Gauge Calculator 🔗
How to Use the Wire Gauge Calculator
Enter current (A), one-way wire length (m), system voltage (V), and maximum allowed voltage drop (%). Formula: VD = (2 × L × I × ρ) / A, where ρ = 0.0172 Ω·mm²/m for copper.
Keep voltage drop below 3% for efficiency. Higher voltage drop wastes energy and can affect device performance. Use thicker wire for long runs or high-current circuits.
DC circuits use both positive and negative conductors, so the total wire length is 2× the one-way distance. Always use the next gauge up from the calculated minimum for safety margin.
FAQ
What is the maximum acceptable voltage drop for a solar system?
Keep voltage drop below 3% for efficiency. For a 12V system, that's 0.36V maximum drop. Higher voltage drop wastes energy and can cause equipment to malfunction or shut down.
Why is DC wire sizing different from AC wire sizing?
DC circuits carry current in both directions through separate positive and negative conductors, so total wire length is 2× the one-way distance. DC systems also operate at lower voltages, requiring higher current for the same power, which demands thicker wire.
What wire gauge should I use between my solar panels and charge controller?
Use the wire gauge calculator with your panel's short-circuit current (Isc) and the distance from panels to controller. Typically AWG 10–6 for runs under 30 feet at 20–40A.
Should I use copper or aluminum wire for solar systems?
Copper wire is strongly preferred for solar systems. Aluminum wire has higher resistance (requires 2 gauges thicker), is prone to oxidation at connections, and is not suitable for most solar connectors. Always use copper for DC wiring.
How do I handle wire sizing for a 48V system vs 12V?
Higher voltage systems carry less current for the same power (P=V×I), allowing thinner wire. A 1,000W load at 12V draws 83A (needs AWG 2), while at 48V it draws only 21A (AWG 10 suffices). This is a major advantage of higher voltage systems.