The Siemens 5SM3346-0KL is a 4-pole SENTRON residual current circuit breaker (RCCB), type AC, rated 63 A at 400 V AC with a 30 mA trip threshold. The 63 A rating means it can serve as the main incoming RCCB for a sub-distribution board or protect a group of downstream MCBs feeding high-load circuits like ovens, heat pumps, or EV chargers. Type AC means it detects sinusoidal alternating residual currents only. For circuits with non-linear loads (switched-mode power supplies, LED drivers, VFDs) that generate pulsed or high-frequency leakage, a Type A or Type F RCCB would be required. This part is a straight AC-only device — no short-time delay, no selective characteristic.
Terminals accept solid or stranded conductors from 1.5 mm² up to 25 mm², with a recommended tightening torque of 2.5 to 3 N·m. The N conductor is on the left side of the device (N left variant), so plan your busbar and cable routing accordingly — this matters if you're replacing a unit with the neutral on the right. The device is finger and back-of-hand safe per the shock protection class, but it must live inside a closed panel.