The Siemens SENTRON 5SU9354-7KK20 is a combined RCD and MCB in one 2-module-wide (36 mm) package — an RCBO protecting a single-phase final circuit. It carries a 20 A rated current with C-curve trip characteristic for moderate inrush loads (lighting banks, small motor circuits, control transformers) and integrates a 30 mA type A residual-current element for sinusoidal and pulsating DC fault currents.
The C-curve trips between 5× and 10× In, so a 20 A unit holds through the 100–200 A inrush typical of a contactor coil or a bank of LED drivers. The 30 mA type A residual element catches both sinusoidal AC faults and pulsating DC from rectified loads (variable-speed drives, switched-mode supplies) — a common requirement in modern commercial panels. The 10 kA SCCR at 230/240 V is the standard domestic and light-commercial fault level; if your point-of-supply fault current exceeds that, you need an upstream current-limiting device. The 1P+N construction switches the line pole and breaks the neutral, but the neutral pole is not overcurrent-protected — only the line pole has the thermal-magnetic trip. That is normal for single-phase RCBOs; the neutral opens with the line on a fault. The 2 MW width (36 mm) means it occupies two standard 18 mm DIN positions.
The 77 mm depth plus 70 mm installation depth leaves clearance behind a standard 80 mm deep enclosure. Ambient range -40 to 75 °C covers unheated plant rooms and outdoor-rated enclosures.