Solar Wire Gauge Calculator: Find the Right DC Wire Size for Your System

 

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Solar Wire Calc

AWG / mm² Wire Gauge Calculator · Off-Grid & On-Grid

⬡ System Parameters

System Voltage (V)

Current (Amperes)

A

Or enter wattage below to auto-calculate

Power (optional)

W

Wire Run — One-Way Length

Meters Feet

Max Voltage Drop

2% recommended for critical loads

Temperature Rating 60°C (NM cable, older wiring) 75°C (Most household wiring) 90°C (THHN, outdoor solar cable)

Higher-rated wire can handle more current

PV String Isc (Short Circuit Current)

A

Number of Strings in Parallel

⬡ Wire Type & Circuit

Circuit Type DC Circuit (Solar panels → Battery) DC Load (Battery → Loads) AC Circuit (Inverter output / Grid)

Wire Material

Copper: resistivity 1.72×10⁻⁸ Ω·m

Display Units

Installation Method Free air / conduit (single cable) Bundled (3-6 cables together) Bundled (7-24 cables) Buried in ground In conduit, buried

Derating factor: 1.0×

Safety Margin

NEC 690.8: 125% · Solar: 156% of Isc

⬡ Quick Reference

AWG	mm²	Max A (Cu)	Common Use
18	0.82	14	Small DC loads
16	1.31	18	LED lighting
14	2.08	25	15A branch circuits
12	3.31	30	20A branch circuits
10	5.26	40	Small panels / loads
8	8.37	55	Medium solar strings
6	13.3	75	Inverter cables
4	21.2	95	Battery bank cables
2	33.6	130	Large inverters
1/0	53.5	170	High-current DC
2/0	67.4	195	Battery interconnects

Enter parameters and click Calculate to see wire recommendations

⬡ Recommended Wire

AWG Size

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Cross-Section

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mm²

Design Current

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Amperes

Voltage Drop

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—

Wire Resistance

—

Ω (total run)

Power Loss

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Watts lost

WIRE

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⬡ Sizing Comparison

AWG	mm²	Capacity	V-Drop	P-Loss	Note

⬡ Installation Notes