RCBO with Type A residual current and C characteristic
The Siemens SENTRON 5SU1324-7FP25 is a 2-pole residual current operated circuit breaker (RCBO) combining overcurrent protection and residual current detection in a single 36 mm wide (2 MW) DIN-rail module. It carries a 25 A rated current at 30 °C ambient and trips on residual fault currents of 30 mA, Type A — meaning it detects sinusoidal AC faults and pulsating DC fault currents up to 6 mA ripple, per IEC 60755. The C tripping characteristic (5–10× In magnetic release) suits it for circuits with moderate inrush loads like small motors, lighting banks, and control transformers in residential and light commercial distribution boards.
Breaking capacity and thermal derating
The 10 kA breaking capacity per EN 60898 means this RCBO can safely interrupt fault currents up to 10 kA at the rated voltage — sufficient for most domestic and small commercial sub-distribution boards where the prospective short-circuit current stays under that threshold. The thermal derating curve is published: 24 A at 40 °C, 23.5 A at 45 °C, 23 A at 50 °C, 22.5 A at 55 °C, and 22 A at 60 °C (–). If the distribution board is installed in a warm enclosure or near other heat sources, apply the appropriate derating factor from that table rather than relying on the 30 °C figure.
Mounting and environmental ratings
The 5SU1324-7FP25 snaps onto standard DIN rail (EN 60715) and occupies 2 modular width units (36 mm). Mounting position is any, which simplifies panel layout — no restriction to upright orientation. The IP20 rating applies only when the distribution board is installed with connected conductors; the device itself is not sealed against dust ingress beyond finger-safe touch protection. Ambient temperature range spans -40 °C to 70 °C, covering unheated utility rooms and outdoor-adjacent enclosures. Pollution degree 3 and overvoltage category III confirm suitability for fixed installations within the building distribution network.