What this RCBO is and where it fits
The Siemens 5SU1354-7LB32 is a 2-pole (1P+N) residual current circuit breaker with overcurrent protection (RCBO) from the SENTRON 5SU1 series. It combines a 32 A rated current with a 10 kA breaking capacity per EN 60898 and a Type A fault-current sensitivity, meaning it detects both sinusoidal AC residual currents and pulsating DC fault currents — the standard requirement for circuits feeding single-phase electronics, variable-speed drives, or appliances with rectified front ends. The tripping characteristic C suits moderate inrush loads like motor starters and lighting banks. The short-time delayed G and super resistant K design provides selectivity against nuisance tripping from transient leakage or short-duration ground faults, which is useful in distribution boards feeding multiple downstream RCBOs. Mounting is straightforward: the unit occupies 2 width units (36 mm) on a DIN rail, with a depth of 77 mm and height of 90 mm. It can be installed in any position, and the supply cord can enter from either top or bottom, which simplifies panel layout. The IP20 rating is typical for enclosed distribution boards — the protection is complete once the board cover is fitted and conductors are connected.
Thermal derating and ambient limits
The RCBO is rated for a full 32 A at 30 °C ambient, but the current must be derated as the enclosure temperature rises: 30.4 A at 40 °C, 29.76 A at 45 °C, 28.8 A at 50 °C, 27.84 A at 55 °C, 27.2 A at 60 °C, 25.92 A at 65 °C, and 24.64 A at 70 °C. The operating ambient range spans -40 °C to +75 °C. In a crowded panel with multiple breakers, the effective load current may need to be reduced — plan the thermal budget accordingly.
Compliance and documentation
The 5SU1354-7LB32 is halogen-free and silicon-free, meeting material restrictions common in clean manufacturing environments. It carries the standard SENTRON approvals (CE, UKCA, EAC, and IEC/EN 60898 certification for the 10 kA breaking capacity). The product designation per DIN EN 61346-2 and DIN EN 81346-2 is F. For compliance documentation (RoHS, REACH, UL), the manufacturer provides declarations and certificates on request — these are typically included with the shipment or available through the distributor.