The ABB GSH204 AC-S-C50/0.3 is a 4-pole, 50A, Type AC, C-curve, Selective ("S"-type) Residual Current Circuit Breaker with Overcurrent Protection (RCBO). This is a highly specialized and advanced protective device that combines the full functionality of an RCBO (overload, short-circuit, and earth leakage protection) with a built-in time-delayed trip characteristic for residual currents. The "S" (Selective) suffix indicates it incorporates a short time delay (typically 10-40 ms) before tripping on a residual current fault. This allows it to be used in a coordinated protection scheme with downstream instantaneous ("G"-general use) RCDs/RCBOs, ensuring that only the circuit closest to the fault trips, minimizing unnecessary power outages.
