The Siemens 5SU1374-7DK81 is a 4-pole RCBO from the SENTRON 5SU1 series, combining overcurrent protection and residual current detection in a single 11-module-wide unit. The Type B+ fault current detection handles AC, pulsating DC, smooth DC, and high-frequency residual currents — covering modern electronics, VFDs, and UPS systems that generate complex leakage profiles.
Thermal derating and conductor sizing
The 100 A rating holds only at 30 °C. At 40 °C it derates to 92.5 A, at 50 °C to 85 A, and at 60 °C to 77 A. In a warm panel near other heat sources, the effective continuous current is lower than the nameplate — plan the load accordingly.