The Siemens SENTRON 5SM2346-0 is a 4-pole residual current device (RCD) rated for 63 A at 400 V AC with a 30 mA trip threshold, type AC. It is designed as a companion RC unit for the 5SL4 miniature circuit breaker series, fitting into the same modular enclosure footprint at 3 modular width units wide.
What the ratings mean for fit
The 63 A rating at 400 V AC is the continuous current the device can carry under normal conditions — sized for a main incoming supply or a large subfeed in a three-phase distribution board. The 30 mA trip threshold is the standard sensitivity for personnel protection (indirect contact) per IEC 60364, catching leakage to earth before it reaches a dangerous level. Type AC means it detects sinusoidal AC residual currents only — suitable for circuits with resistive, inductive, or conventional electronic loads that don't generate pulsed DC fault currents. For circuits with rectifiers, VFDs, or switched-mode supplies, a type A or F RCD would be needed instead.
Temperature derating — the real continuous current
The 63 A rating holds at 40 °C ambient. Above that, the device derates: 58.6 A at 40 °C, 58.59 A at 45 °C, 56.7 A at 50 °C, 54.81 A at 55 °C, 53.55 A at 60 °C, 52.29 A at 65 °C, and 50.4 A at 70 °C (–). If the panel ambient runs at 50 °C, the effective continuous rating drops to 56.7 A — a 10% reduction that matters for a fully loaded circuit. The maximum operating ambient is 45 °C, with storage extremes from -40 °C to 75 °C.
Mounting and integration
Mounts on a standard DIN rail (REG fastening,) in any position. The 70 mm depth and 123 mm width match the 5SL4 breaker footprint, so it clips directly alongside or downstream of the companion MCB in the same distribution board. Installation depth is 70 mm. Overvoltage category III means it's rated for fixed-installation downstream of the main distribution board — not for the service entrance itself.