Overview
The Siemens 5SM3654-6 is a 4-pole residual current operated circuit breaker (RCCB), type A, rated at 40 A with 300 mA sensitivity and an AC rated voltage of 500 V. It carries a 10 kA short-circuit rating and mounts on DIN rail (REG) with IP20 finger-safe protection.
Function & operation
This RCCB detects earth leakage currents via a differential transformer; an imbalance exceeding 300 mA trips the mechanism within the listed switching cycles.
Applications
As a 4-pole RCCB the 5SM3654-6 is used in three-phase distribution boards for commercial and industrial buildings, protecting circuits feeding socket outlets, lighting, and small machinery. The 300 mA sensitivity suits sub-distribution and main switchboard protection where nuisance tripping from leakage currents in long cable runs must be avoided, while still providing earth-fault protection.