The Siemens 5SU1654-1KV06 is an FI/LS combination unit — a combined residual-current device and miniature circuit breaker (RCBO) in a single 1+N-pole module. The D=70 mm dimension refers to the width of the enclosure, fitting standard Siemens distribution boards.
The 6 A C-curve overcurrent element protects final circuits supplying resistive and light inductive loads — lighting, small appliances, control transformers — where inrush is moderate. The 300 mA Type AC residual-current element responds to sinusoidal AC fault currents only; it is not suitable for pulsating DC or smooth DC fault conditions (Type A or Type B would be required for drives, UPS, or EV charging circuits).
Deployment context
The 70 mm wide module snaps onto DIN rail inside a Siemens distribution board or similar enclosure. The Type AC residual element means it is intended for general-purpose AC circuits where no electronic loads generate non-sinusoidal fault currents. Common applications include lighting circuits, socket outlets in offices or residential buildings, and small motor circuits with contactor control.