What it is and what it does
The Siemens 5SM9346-6 is a 4-pole residual current (RC) unit from the SENTRON series, designed as an electronic add-on for the 5SL4 miniature circuit breaker family. It combines overcurrent and residual current protection in one assembly — a common approach in final-distribution boards where space is tight and selectivity matters. The unit is rated for 63 A at 400 V AC, 50 Hz, with a 30 mA Type A residual current trip. Type A means it detects sinusoidal AC fault currents plus pulsating DC fault currents, covering most modern electronic loads like switched-mode power supplies and variable-speed drives.
Key ratings and what they mean for fit
The 63 A rating governs the maximum continuous load. The 30 mA trip threshold is the standard for personal protection against direct contact.
Mounting and panel integration
Mounts on standard DIN rail in any position. The unit occupies 3 width units — 54 mm of rail space — and requires 70 mm installation depth. Terminal capacity accepts solid conductors 0.75 to 35 mm² and stranded 0.75 to 25 mm².