The Siemens 3RV1021-1HA10-ZW95 is a SIRIUS motor protection circuit breaker — a 3-pole device sized for a 3 kW motor at 400 V AC, with a continuous current rating of 8 A and Trip Class 10 thermal overload protection.
Any mounting position works. Screw terminals on both main and auxiliary circuits accept 1 to 2.5 mm² solid or stranded (two conductors per clamp), or 2.5 to 6 mm² for a single conductor. AWG 14 to 10 equivalent. Zero clearance needed at the sides or rear — 0 mm backwards and side spacing. IP20 on the front face means finger-safe from the panel front; the body itself is open-frame behind the panel, so enclosure selection needs to account for that.
Trip Class 10 means the thermal bimetal trips within 10 seconds at 7.2× the current setting — standard for standard-duty motor starting where the acceleration time is under 10 seconds. For longer ramp times (high-inertia loads), a Class 20 or 30 would be needed. The 15 operations per hour maximum at AC-3 duty governs how often you can cycle this breaker under motor load — fine for a pump or fan cycling a few times an hour, but not for a rapid-reversing application. Rated insulation voltage 690 V, surge voltage resistance 6 kV. Power dissipation 9.25 W at rated current (3.1 W per pole).