What this RCBO covers
The Siemens 5SU1344-1RC63 is a 4-pole RCBO (residual current circuit breaker with overcurrent protection) from the SENTRON series, rated 63 A with a C tripping characteristic and Type AC 30 mA residual-current sensitivity. It combines overcurrent and earth-fault protection in a single 7-module-wide unit, saving a DIN-rail position compared to separate MCB + RCCD pairs. Breaking capacity is 10 kA per EN 60898 and 15 kA per IEC 60947-2 at 415 V AC — the higher IEC figure gives coordination headroom for industrial panel designs where the prospective fault current exceeds the residential standard. Rated insulation voltage is 440 V AC, overvoltage category III, pollution degree 2 — suitable for fixed-installation distribution boards in commercial or light industrial environments where the supply is solidly grounded and the environment is dry.
Lifecycle and sourcing posture
No official successor has been published — this remains the current catalog number for a 63 A, 4-pole, Type AC 30 mA RCBO in the SENTRON line.
Panel fit and mounting
Occupies 7 modular width units (126 mm) on a DIN rail, with a depth of 70 mm and height of 90 mm. The supply can enter from either the top or bottom terminals, and the unit can be mounted in any orientation — useful when panel layout forces a horizontal or inverted position. IP20 protection applies when installed in a distribution board with connected conductors — the RCBO itself is not rated for exposed or washdown locations. Operating temperature range is -40 °C to 75 °C, with up to 95% humidity — covers unheated electrical rooms and outdoor enclosures in temperate climates.
Selectivity and coordination note
Energy limitation class 3 means the RCBO limits let-through energy during a fault, aiding downstream selectivity with standard MCBs. The C-curve (5–10× In magnetic trip) is the common choice for motor-starter and general-distribution circuits where inrush is moderate. Rated surge voltage resistance is 4 kV — adequate for overvoltage category III installations where the device is downstream of the main distribution board.