The Siemens 5SU1654-0KV16 is an FI/LS-protector — a combined residual-current device (RCD) and miniature circuit breaker (MCB) in one 1+N-pole module, rated B-curve 16 A, 10 kA breaking capacity, 300 mA Type AC residual sensitivity, in a 70 mm-wide housing.
The 70 mm width (4 module spaces on a standard DIN rail) is wider than a single-pole RCBO — check your enclosure fill factor before committing. Spring-cage terminals accept 0.2–2.5 mm² solid or ferruled stranded; strip length 8 mm avoids whiskers under the cage. The 1+N-pole configuration switches the phase and breaks the neutral through the RCD, so the neutral bar in the board must be broken at this position.