What this RCBO does on the panel
The Siemens 5SU1653-1KV10 is a combined residual-current device and miniature circuit breaker — an RCBO — in a single 70 mm-wide module. It protects a 1+N-pole final circuit against overload (C-curve, 10 A rated current), short-circuit (4.5 kA breaking capacity), and earth leakage (Type AC, 300 mA trip threshold).
The 10 A C-curve thermal-magnetic trip suits lighting, socket outlets, and small motor loads with moderate inrush — typical for residential or light commercial final circuits. The 300 mA residual-current threshold is higher than the standard 30 mA for personal protection; it is intended for equipment protection or circuits where nuisance tripping from leakage is a concern, such as long cable runs or loads with inherent leakage. The 70 mm width (4 module spaces) is standard for 1+N-pole RCBOs on DIN-rail enclosures.