The Siemens 5SM3416-6KL is a SENTRON residual current operated circuit breaker (RCCB), 2-pole, Type A, rated 63 A at 230 V AC with a 100 mA trip threshold.
The 63 A rated current at 50 Hz means this RCCB carries the full load of a typical residential or light commercial submain — think a lighting and general-purpose socket circuit feeding a small workshop or a panel in a pump house. The 100 mA residual trip is the slower, ground-fault protection level, not the 30 mA personal-shock threshold; it's meant for equipment protection or circuits where nuisance tripping from leakage is a concern, like older motors or long cable runs. Type A detection catches pulsating DC fault currents on top of sinusoidal AC — that covers modern electronics with half-wave rectifiers, switched-mode power supplies, and variable-speed drives downstream. If your line has VFDs or LED drivers, Type A is the right call over Type AC. The instantaneous design means no intentional time delay; it trips as fast as the fault current lets it. Ambient temperature range of -25 to +45 °C and storage down to -40 °C means it handles unheated electrical rooms and outdoor enclosures in most climates, though you'll want to keep the panel ventilated if it's sitting in direct sun.
Mounts on DIN rail (REG) in any position — the device is 36 mm wide (2.5 width units), 90 mm tall, and 70 mm deep, which is a standard footprint for a 2-pole RCCB. The screw terminals accept 1.5 to 25 mm² solid or stranded copper, tightened to 2.5 to 3 N·m. That's enough lug for a 25 mm² incoming feed and daisy-chaining through the busbar system. Supply can land top or bottom, which saves head-scratching when you're retrofitting into an existing board where the feed comes up from the bottom.