What it is and what it does
The Siemens 5SU1653-7KV25 is an FI/LS-Protector (RCBO) combining residual-current and overcurrent protection in a single 1+N-Pol module. It's rated Type A for pulsating DC and AC fault currents, with a rated residual current IΔn of 300mA and a short-circuit breaking capacity of 4.5kA. The thermal-magnetic release is a C-curve 25A, so it trips on overload between 5x and 10x In — typical for motor and lighting circuits with moderate inrush. The 70mm depth fits standard Siemens distribution boards.
Deployment context
Snap-on mounting for DIN rail enclosures. The 1+N-Pol form factor occupies a single module width, so it retrofits into existing Siemens distribution boards or any standard 18mm-spaced DIN rail panel. The Type A sensitivity (300mA) makes it suitable for circuits with electronic loads — switched-mode power supplies, VFDs, or appliances with rectifiers — where pure AC-sensitive RCDs might nuisance-trip.