The Siemens 5SU1354-1LV25 is a combined residual-current device and miniature circuit breaker (RCBO) — an FI/LS-protector — in a 1+N-pole form factor. It combines Type AC residual-current detection at 30 mA with a C-curve overcurrent trip at 25 A, all rated for a 10 kA short-circuit breaking capacity. The G-type designation indicates a short time delay (typically 10 ms) to coordinate with downstream devices and reduce nuisance tripping on transient surges.
What the ratings mean for the panel
The 30 mA sensitivity covers the standard personnel-protection threshold per IEC 60364 — it clears earth faults before they reach a dangerous let-through energy level. The 10 kA breaking capacity at the rated voltage means it can safely interrupt a bolted fault up to that level without rupturing or cascading upstream; that's typical for final subcircuits in a distribution board where the prospective fault current is known to be under 10 kA. The C-curve (5–10× In) is sized for loads with moderate inrush — think small motors, lighting banks, or control transformers — not for purely resistive circuits (B-curve) or high-inrush transformers (D-curve). The 70 mm width (about 4 module spaces on a DIN rail) is standard for a 1+N RCBO in the Siemens 5SU family, so it slots into any 18 mm-module enclosure without crowding.