What this contactor is and where it fits
The 3RT1016-1BB42-ZW95: The size S00 frame (45 mm wide, 57.5 mm high, 72 mm deep) is the smallest in the SIRIUS contactor family, designed for compact control panels where every millimeter of DIN rail counts. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022.
What the ratings mean for your motor load
The 4 kW rating at AC-2 duty at 400 V tells you this contactor is sized for slip-ring motor switching — the kind of load that sees moderate inrush but requires reliable arc extinction during start/stop cycles. For AC-4 reversing or inching duty at 400 V, the rated operational current is 8.5 A, which is the figure to use when the contactor sees frequent plugging or jogging. The DC coil draws 3.3 W during both pick-up and hold, which simplifies the control transformer sizing — no spike at pull-in to account for. The pick-up threshold is 85% of rated voltage (20.4 V for a 24 V coil), and the drop-out is 1.1× rated (26.4 V), so the contactor stays latched through a sag but drops cleanly on overvoltage.
Wiring and coordination
Main circuit terminals accept 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or up to 2× (0.75 to 4 mm²) solid or stranded copper. For AWG, that translates to 2× (20 to 16), 2× (18 to 14), or 1× 12. Screw-type terminals — no spring-cage here, so factor in the extra torque-check step during panel build. For Type 2 coordination (no weld risk after a short circuit), the required upstream fuse is gL/gG 20 A. For Type 1 coordination (device may be damaged but no fire hazard), use gL/gG 35 A. Pollution degree 3 means it is rated for industrial environments with conductive dust or occasional condensation — no conformal coating needed for most panel applications.