DC Cable Selection Based on Voltage & Current

Core Selection Rule: Calculate current → Select wire gauge → Confirm cable length → Choose insulation sheath

1. Core Reference Data (Copper PVC Cable, Ambient Temperature Rated Current)

2. Step-by-step Selection

Step1 Calculate operating current

Step2 Upsize gauge by cable length (Critical for low voltage)

• Length＜1m: Follow the table above directly
• 1~3m run: Upgrade wire gauge by one size (0.5mm² → 0.75mm²)
• Length＞3m: Upgrade another size to avoid insufficient terminal voltage
  Recommended voltage drop limit: ≤0.5V for 12V circuits; ≤0.25V for 5V circuits

Step3 Match DC barrel connector

• ≤3A: Standard 5.5×2.1mm DC plug with 0.3/0.5mm² wire
• 3~8A: Heavy-duty 5.5×2.5mm DC plug, ≥0.75mm² wire
• ≥10A: Discard round DC plugs; use terminal blocks or aviation connectors instead

3. Quick Selection Chart for Common Applications

1. 5V ≤2A (Phone/ small mainboard): 0.3mm² solid copper wire
2. 12V ≤3A (CCTV/LED lighting): 0.3~0.5mm²
3. 12V 3~5A (Router/HDD/LED strip): 0.5mm²
4. 12V 5~8A (Water pump/high-power lamp): 0.75mm²
5. 24V heavy load: One gauge smaller than equivalent 12V wiring (Higher voltage = lower current)

4. Supplementary Notes

1. Material: Pure copper > Copper-clad aluminum (CCA); upsize wire by one grade if using CCA cable
2. High-temperature enclosed installation: Derate current capacity by 20% and use oversized wire
3. Parallel wiring: Total cross-section = sum of individual wires (Two 0.5mm² ≈ single 1.0mm²)

Provide operating voltage, wattage/current and cable length for precise wire sizing recommendation.