S00 power contactor with spring-loaded terminals
The Siemens 3RT1016-2BB42-ZW97 is a SIRIUS S00 power contactor with a 24 VDC coil and spring-loaded terminals for the main current circuit. It snaps onto a 35 mm DIN rail per DIN EN 50022 and occupies 45 mm of panel width — a standard slot in any control cabinet layout. The IP20 finger protection on the front and terminals means it's safe for open-panel installation where operators reach in for maintenance.
Ratings that decide the fit
The headline rating is 10 A in AC-12 duty (resistive loads at line frequency). That's the maximum continuous current the main contacts can carry when switching resistive heaters, lighting banks, or transformer primaries. For motor loads, the AC-2 rating at 400 V is 4 kW — that's the figure for wound-rotor motors where the contactor makes and breaks under load. The AC-4 rating at 400 V is 8.5 A, which governs plugging and inching duty on squirrel-cage motors; that's the number a drive designer looks at for reversing or jogging circuits. At higher voltages the contactor delivers 4.5 kW at 500 V and 5.5 kW at 690 V — both AC-3 duty, the standard for starting squirrel-cage motors and disconnecting after they're up to speed. The coil pulls 3.3 W on closing and holds at 3.3 W, so the DC supply needs to source about 140 mA continuous per contactor. Operating temperature spans -25 to +60 °C, and the pollution degree 3 rating means it's suited for industrial environments with conductive dust or occasional condensation.
Termination and wiring
Spring-loaded terminals accept 2x (0.25 to 2.5 mm²) solid or stranded wire, or 2x (24 to 14 AWG). No screwdriver torque required — strip 8 mm, push in, done. The side-by-side mounting clearance is 6 mm, so you can pack contactors tight on the rail without derating, provided the ambient stays within the -25 to +60 °C window.
Short-circuit coordination
For Type 2 coordination (no damage to the contactor after a fault), the required upstream fuse is gL/gG 20 A. For Type 1 coordination (contactor may need replacement after a fault), use gL/gG 35 A. These are the fuse sizes that limit let-through energy so the contactor's welds stay within acceptable limits.