It provides short-circuit and overload protection for control transformers and similar inductive loads up to 690 V.
The S00 footprint (97 × 45 × 97 mm) fits the common panel cutout for this frame size. Any mounting position is allowed, so it can be oriented to fit tight enclosures. Clearance: 50 mm above and below, 30 mm to the side, 0 mm forward and backward — meaning it can sit flush against the back panel, which simplifies wiring in shallow cabinets.
Rated for 20...690 V AC, with a breaking capacity of 100 kA at 240 V, 400 V, 500 V, and 690 V — that's a high-fault rating that covers most industrial panel applications without needing upstream current-limiting fuses. The 0.1 kW power rating at 230 V is the maximum transformer load it can protect; for larger transformers you step up to the next SIRIUS frame size. No ground fault detection, so that function must be handled externally if required.
Screw-type terminals on the main current circuit accept solid or stranded wire: 2 × (0.75...2.5 mm²) or 2 × 4 mm². The screwdriver shaft needs a 5 to 6 mm diameter. This is a standard M3 terminal for the main contacts — no special crimp tool needed. Keep the strip length clean and the torque within the terminal spec (not listed here, but typical for SIRIUS S00 is 1.2...1.5 Nm).