What It Is and Where It Fits
The Siemens 3RT1017-1HB42-ZW95 is a SIRIUS power contactor in size S00, designed for switching motor loads and resistive loads in industrial control panels. It is rated for screw and snap-on mounting onto a 35 mm DIN rail per DIN EN 50022, so it integrates directly into standard enclosure layouts without adapter plates. Its 45 mm width and 57.5 mm height keep the footprint compact for high-density panel builds, and the 72 mm depth leaves clearance behind the DIN rail for wiring.
Key Ratings and What They Mean for Your Circuit
The magnet coil is rated 24 VDC, with a closing and holding power of 2.3 W — a low-hold design that reduces heat buildup in the panel and lets you use a smaller DC supply than an equivalent AC coil. For motor duty, the AC-4 rating at 400 V is 8.5 A — that is the current it can switch under severe starting or reversing conditions (plugging, inching). If your application is AC-3 (normal starting of squirrel-cage motors), the contactor handles higher currents; the AC-4 figure is the conservative one for high-stress cycles. The auxiliary contact block (integrated) carries 10 A at 24 VDC, 6 A at 230 V, and 3 A at 400 V — these are the ratings for the built-in N/O and N/C contacts used in control logic or signaling. Short-circuit coordination is specified: type 2 coordination requires a gL/gG fuse of 20 A; type 1 allows up to 35 A. That means with a 20 A fuse, the contactor remains usable after a fault; with a 35 A fuse, it may need replacement but the circuit clears.
Wiring and Termination
Main current circuit terminals are screw-type, accepting 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) solid or stranded conductors. AWG equivalents are 2x (20 to 16), 2x (18 to 14), and 1x 12. This covers most panel wiring up to 4 mm² without needing ferrule adapters. Side-by-side mounting is permitted with a 6 mm spacing to adjacent devices, which saves rail space in dense layouts.
Environmental and Protection
IP20 on the front and terminals means it is protected against solid objects larger than 12 mm (fingers, tools) but not against moisture — install it inside a panel with at least IP54 enclosure for washdown or outdoor environments. Operating temperature range is -25 to +60 °C, with a maximum altitude of 2,000 m without derating. Above that, expect reduced dielectric strength and switching capacity. Pollution degree 3 per IEC 60947-1 means it is suitable for industrial environments with conductive pollution (dust, condensation) inside the panel.