The ABB GSH204 AC-D40/0.03 is a 4-pole, 40A, Type AC, D-curve Residual Current Circuit Breaker with Overcurrent Protection (RCBO). This advanced protective device is engineered for three-phase four-wire circuits that supply equipment with extremely high inrush (starting) currents. It integrates complete protection against overloads, short-circuits, and earth leakage currents (30mA) into a single compact unit. The defining feature is its D-curve overcurrent characteristic, which features a very high magnetic trip threshold (10-20 times the rated current) to withstand the intense but brief startup surges of motors, transformers, and other inductive loads without nuisance tripping, while still providing critical life-saving protection against electric shock.
