What it is and where it fits
The Siemens 3RT1015-2VB42 is a SIRIUS power contactor in the S00 frame size, designed for switching motor loads and resistive loads in control panels. It carries a 24 VDC coil with an integrated diode surge suppressor, and the main circuit connects via spring-loaded terminals — no screw torque to verify, just strip and push. Mounting is screw or snap-on onto 35 mm DIN rail per EN 50022, which is the standard rail in every panel I've opened. The 45 mm width and 60 mm height keep it compact for dense layouts, and the 73 mm depth leaves room for wiring in a shallow enclosure.
Key ratings and what they mean for your BOM
Rated operational current is 10 A at 24 V, but the real motor-switching number is the AC-3 rating: 3.5 kW at 500 V and 4 kW at 690 V. That's the figure that tells you whether this contactor handles your 5.5 HP motor at 480 V — it does, with headroom. For resistive loads (AC-1), the maximum operating current is 10 A. The coil pulls 1.4 W to close and holds at 1.4 W DC — that's a low continuous drain for a PLC output or a 24 VDC power supply. The integrated diode means you don't need an external flyback diode across the coil, but verify polarity: reverse voltage kills the diode and the coil driver. Operating temperature range is -25 to +60 °C, which covers most indoor panel environments. Pollution degree 3 means it's rated for conductive pollution environments — typical for industrial control rooms where some dust and humidity are present.
Wiring and coordination
Spring-loaded terminals accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). Strip length is standard for spring clamps — about 8 to 10 mm. No screwdriver needed for the power connections, which saves time on repetitive wiring. For Type 1 coordination (no damage to the contactor after a short circuit, but may need contact replacement), use a 35 A gL/gG fuse upstream. For Type 2 coordination (contactor remains fully functional after a fault), use a 20 A gL/gG fuse. That's the spec for sizing your branch circuit protection. Side-by-side mounting is allowed, which means you can gang multiple contactors on the rail without derating — but check the 6 mm clearance at the side if you're mixing with heat-generating devices like solid-state relays.
Lifecycle and sourcing reality
The 3RT1015-2VB42 is a specific variant: S00 frame, 24 VDC coil with diode, spring terminals. If your panel was built around a screw-terminal version (like the 3RT1015-1BB42), the spring-terminal variant drops into the same footprint and same DIN rail slot — just different wiring method. If your existing panel uses a 3RT1016-2AP02 (larger frame or different coil voltage), the physical size and terminal layout differ; verify the mounting hole pattern and coil voltage before swapping.