What the ratings mean for your BOM line
The 3RT1015-2BA41: The 3.5 kW at 400 V AC-3 rating is the number that decides fit for a motor load — AC-3 covers starting and stopping squirrel-cage motors, so that's the real-world switching capacity. For heavy-duty jogging or inching (AC-4), it's rated 6.5 A at 400 V, which is about 3 kW for a typical 400 V motor. The AC-12 rating of 10 A covers resistive loads like control transformers or heaters. Short-circuit coordination is specified: with type 2 coordination, use a gL/gG fuse rated 20 A; with type 1 coordination, a 35 A fuse. That's the factory-recommended protection for the main circuit — don't oversize the fuse or you lose the coordination guarantee. The coil operates at 24 V DC with a closing and holding power of 3.3 W. That's a constant-holding DC coil — no AC hum, and the power draw stays flat whether it's picking up or sealed in. The operating temperature range is -25 to +60 °C, with pollution degree 3 (conductive pollution typical in industrial enclosures). The contactor is rated for operation up to 2,000 m altitude without derating. Above that, you'd need to account for reduced air density affecting arc extinction.
Panel integration and wiring
The 45 mm width and 73 mm depth fit the standard S00 DIN-rail envelope. Side-by-side mounting is permitted, with a 6 mm clearance required at the side for heat dissipation. The spring-loaded terminals accept 2x (0.25 to 2.5 mm²) solid or stranded conductors, or 2x (24 to 14 AWG). No screwdriver torque check needed — spring cages are vibration-resistant and faster to wire. IP20 on the front and at the terminals means finger-safe but not protected against water ingress — keep it inside a panel with at least an IP54 enclosure.