What it is and what drives the fit
The 3RT1017-2BB41-ZW98: The AC-4 switching rating at 400 V is 8.5 A — that is the motor-reversing or plugging duty cycle, where the contactor makes and breaks locked-rotor current. For straight AC-3 motor starting, the power rating at 400 V is 5.5 kW. Mounting is screw or snap-on onto 35 mm DIN rail per DIN EN 50022, with side-by-side mounting allowed. The 45 mm width keeps panel density tight.
Terminal and wiring constraints
Spring-loaded main terminals accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). No screw torque to check — just strip and insert. The IP20 front-of-terminal rating means it is safe for finger-probe access inside an enclosure. Coil pickup is 0.85 x rated voltage, dropout at 0.1 x rated. Holding power is 3.3 W DC — negligible thermal load in a crowded panel.
Coordination and short-circuit protection
Type 2 coordination (no welding after a fault) requires a gL/gG fuse rated 20 A. Type 1 coordination (device may be damaged but no fire risk) allows a 35 A fuse. For selectivity studies, the 1.1 full-scale value is the thermal overload release setting. Degree of pollution 3 means the contactor is rated for conductive contamination — typical in industrial control panels without climate control.