UV-stabilised 4 mm² and 6 mm² copper conductors rated 1 000 V DC comply with CPR fire class Cca and resist sheath cracking down to –40 °C. Genuine Stäubli MC4 connectors lock with audible clicks and keep contact resistance below 0.25 mΩ across 25 years. Factory-crimped leads and branch Y-connectors reduce field terminations, boosting reliability on large commercial roofs.