What it is and what it does
The SENTRON 5SU9304-6KK32 is an RCBO — a combined RCD and MCB in one 18 mm wide module. It protects a single-phase 230 V AC final circuit against overload, short-circuit (B-curve, 20 A rated), and earth leakage (30 mA, Type A). Type A means it catches pulsating DC residual currents as well as sinusoidal AC — the standard for circuits with electronic loads like washing machines, LED drivers, or small VFDs. The 10 kA breaking capacity (per EN 60898 and IEC 60947-2) is enough for most domestic and light commercial distribution boards; it safely interrupts a fault current up to that level without welding the contacts. The 1P+N construction switches the live pole and provides a solid neutral through the device — the neutral is not switched but is monitored for residual current. This is the typical European final-circuit RCBO layout. The instantaneous design trips without intentional time delay, so it's the first line of earth-fault protection on a subcircuit.
Fit and panel integration
At 18 mm wide (one modular unit), this RCBO fits a standard DIN-rail enclosure. Depth is 77 mm, height 125 mm, with a 70 mm installation depth into the distribution board. That 77 mm depth includes the 600 mm pigtail — a factory-attached neutral tail that saves wiring time in the panel. The supply can enter from the top or bottom, and the mounting position is unrestricted. IP20 protection is achieved once the board is installed and conductors are connected — normal for inside a distribution cabinet. Overvoltage category III and pollution degree 2 are the standard ratings for fixed-installation distribution boards. The 4 kV surge voltage resistance means it handles transient overvoltages from the mains without damage. The 1 kA surge current (8/20 µs waveform) is the impulse withstand for lightning-induced surges — typical for residential and light commercial service entrances.
Temperature and environment
Rated for -40 °C to +75 °C ambient, with max 95% humidity. That covers unheated outdoor enclosures in cold climates and hot machine cabinets near the ceiling. The 20 A rating at 30 °C and at AC confirms the thermal performance is consistent across normal operating conditions — no derating curve to chase for most installations.