What it is and where it lands
The 3RT1017-2KB42-0LA0: Mounting is screw or snap-on onto 35 mm DIN rail per EN 50022. The S00 frame is 45 mm wide, 60 mm tall, 123 mm deep — a compact footprint that fits tight gland-plate layouts. Side-by-side mounting is allowed, so you can gang them without derating for heat stacking in a crowded enclosure.
What the ratings mean for fit
The headline motor rating is 5.5 kW at 400 V AC-3 (the standard squirrel-cage motor duty). Same power rating at 500 V and 690 V — the contactor handles the voltage step without derating the motor kW. For AC-4 (plugging/reversing/inching) at 400 V, the rated operational current drops to 8.5 A, reflecting the heavier switching duty. That's the number to check if your application does frequent reversing or jogging. Coil switching capacity is given at multiple DC voltages: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V. These are the auxiliary contact ratings for the DC control circuit — useful when you're feeding the coil from a PLC output or a remote pushbutton station. The built-in varistor surge suppressor handles the inductive kick on coil dropout, so you don't need an external flyback diode. Ambient temperature range is -40 to +70 °C, which covers most outdoor cabinet and unheated warehouse installs. Pollution degree 3 means it's rated for conductive pollution environments — typical industrial panels without climate control. IP20 on the front and terminals means finger-safe but not washdown-rated; keep it inside the enclosure.
Termination and wiring
Both main current circuit and auxiliary/control circuit use spring-loaded terminals — no screw torque to check, no vibration loosening. They accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). Strip length is standard 8–10 mm for spring-cage. The S00 frame terminals are laid out for straightforward panel wiring; the 45 mm width leaves room for finger duct alongside.
Protection coordination
For type 2 coordination (no damage to the contactor on a short circuit), the required upstream fuse is gL/gG 20 A. For type 1 coordination (contactor may need replacement but the installation is safe), it's gL/gG 35 A. These are the values to hand to the panel builder for the short-circuit protection schedule. The contactor itself has a mechanical life of 30 million operations typical — not a wear item in normal cycling.