When sourcing Solar PV MCBs (Miniature Circuit Breakers), you must prioritize DC-specific ratings. Unlike standard AC breakers, PV MCBs must handle high DC voltages (typically 500V to 1500V DC). Key specs include the Rated Breaking Capacity (Icu), which should ideally be 6kA or 10kA to ensure safety during a fault, and the Rated Current (In), which must be matched to your solar string output. Additionally, ensure the device is non-polarized if your system design requires bidirectional flow, or strictly follow the polarity markings (+/-) for polarized models to prevent catastrophic failure.