Ground-fault circuit interrupter (GFCI) breakers sense leakage of current, e., a live wire touching wet ground, and shut off power in a matter of a fraction of a second to prevent shock. They're necessary on rooftop or coastal installations where rain or wet environments raise. A complete system usually needs coordinated protection on both the DC side and the AC side, including breakers, fuses, and surge protective devices. A circuit breaker protects the system from overloads and short circuits, preventing fires and damage to panels, inverters, and wiring. Using a breaker that is too small can cause it to trip constantly; one that is too large won't. A solar system circuit breaker protects your photovoltaic system from electrical faults.