Siemens 5SU1324-8RC40 RCBO 40 A 2-pole D-curve Type A 30mA

The 5SU1324-8RC40: The 4-module width (roughly 72 mm on a standard DIN rail) fits a standard distribution board or sub-panel. The D characteristic means the magnetic trip operates at 10–20× In (400–800 A instantaneously), which suits motor, transformer, or welding loads that draw a high starting surge without nuisance tripping. The Type A 30 mA residual-current element catches both sinusoidal AC ground faults and pulsating DC faults from electronics — common in modern circuits with rectified loads.