The Siemens 5SU1354-1LV40 is a combined residual-current device and miniature circuit breaker (RCBO), Type AC, rated at 30 mA sensitivity and 10 kA breaking capacity. The 1+N-pole format with C 40 characteristic means it protects a single-phase final subcircuit against both earth leakage and overcurrent, tripping at 5x to 10x rated current for short-circuit faults. The 70 mm width (4 module spaces) fits standard DIN-rail enclosures — plan for the space when populating a distribution board.
What the ratings mean for fit
The 30 mA rated residual operating current (IΔn) is the standard threshold for personal protection against indirect contact and supplementary protection against direct contact in TN and TT systems. Type AC detection responds to sinusoidal AC earth faults — fine for general socket-outlet and lighting circuits where non-sinusoidal leakage is unlikely. The 10 kA rated short-circuit capacity (Icn) means it safely interrupts fault currents up to 10 kA at the declared voltage; verify the prospective short-circuit current at the installation point stays below this. The C 40 overcurrent characteristic (C-curve, 40 A rated) is sized for circuits with moderate inrush — motorized loads, small compressors, or groups of fluorescent fittings — where the magnetic trip threshold of 200 A to 400 A avoids nuisance tripping on startup.