The Siemens 5SU1656-1KV10 is a combined residual-current and miniature circuit breaker (RCBO) — an FI/LS protector — in a single 1+N-pole module. It combines Type AC residual current detection at 300 mA with a C-curve overcurrent trip at 10 A, all rated for a 6 kA breaking capacity. The 70 mm depth (D=70mm) fits standard Siemens distribution boards and most DIN-rail enclosures without crowding the gland plate.
What the ratings mean for fit
The 300 mA IΔn (rated residual operating current) is the trip threshold for earth leakage. Type AC detection means it responds to sinusoidal AC fault currents only — not pulsed DC or smooth DC, so it is suited for general-purpose circuits without electronic loads that generate DC harmonics. The C-curve (10 A rated current) trips at 5–10× In for short-circuit protection, typical for lighting, socket outlets, and small motor circuits. The 6 kA breaking capacity (Icn) is the maximum prospective fault current it can safely interrupt — adequate for most domestic and light commercial distribution boards where the upstream short-circuit capacity is below 6 kA.
Deployment context
Mounts on standard 35 mm DIN rail inside a distribution board or sub-distribution panel. The 1+N-pole format occupies one module width plus neutral, so plan for 2 module-widths per unit in the enclosure layout. The 70 mm depth is shallow enough for most flush-mount and surface-mount enclosures — no need for a deep gland plate or extended box.