The Siemens 5SU1654-1KV16 is a combined RCD and MCB — an FI/LS protector — in a single 1+N-pole module. It carries a C-curve 16 A overcurrent trip and a 300 mA residual-current detection (Type AC, sensitive to sinusoidal AC fault currents).
Panel integration
Width is 70 mm (D=70MM on the label) — that is roughly 4 modular DIN spaces at 17.5 mm each. The 1+N-pole format means it switches the line and breaks the neutral internally, so no separate neutral bar connection is needed downstream of the device. Spring-cage or screw terminals depending on the specific variant; verify the termination type on the unit itself before wiring.