Competency 2 covers the toolkit: MC4 crimping tool (never pliers — a bad crimp is a future arc), DC-rated breakers and fuses, solar cable (UV-resistant, double-insulated, 4 or 6 mm²), battery lugs with heat-shrink, and cable ties rated for sun. Voltage drop discipline: keep DC runs short and fat — a 3% drop at 12 V is only 0.36 V, so panel-to-controller and controller-to-battery runs use generous cable and tight terminations.

1. Strip solar cable to 8 mm
2. Insert into MC4 pin, crimp with the rated tool
3. Tug-test, then click into housing
4. Verify polarity with meter before connecting
5. Label + and − at both ends