RCBO rating and application
The Siemens 5SU9326-7CR32 is a combined residual current circuit breaker with overcurrent protection (RCBO) in a 1P+N form factor. Its 6 kA breaking capacity (Icn) at 230 V AC is sized for final subcircuits in residential and light commercial distribution boards where the prospective short-circuit current stays within that limit. The Type A residual current detection (30 mA) handles pulsating DC fault currents from electronics, rectifiers, and single-phase drives — a step above the basic Type AC that only catches sinusoidal AC earth faults. The C-curve characteristic (32 A rated current In) means the magnetic trip operates at 5 to 10 times In, so it tolerates the inrush from motorized loads, fluorescent ballasts, and small transformers without nuisance tripping. On a 230 V single-phase supply this unit protects both line and neutral; the switched neutral pole opens with the line pole, which is required by some national wiring regulations for RCBOs.
Panel integration notes
The 1P+N width occupies a single modular DIN-rail space (typically 18 mm per pole). In a distribution board, verify that the busbar finger spacing matches the RCBO's incoming terminals — some RCBOs use staggered or captive busbar forks that differ from a standard MCB footprint. The outgoing terminals accept up to 25 mm² conductor; torque to the value marked on the device housing.