What this auxiliary contactor block is and where it fits
The Siemens 3RH2140-1BM40-ZX95 is a size S00 auxiliary contactor block with 4 normally-open instantaneous contacts, designed to snap onto a 35 mm DIN rail or screw-mount in a control panel alongside a SIRIUS contactor or as a stand-alone switching element. Rated for 10 A at both 24 V and 230 V, it handles pilot-duty and signal-level loads across a wide voltage range — 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 3 A at 400 V, 2 A at 500 V, 1 A at 690 V, and lower currents at 440 V (0.5 A) and 600 V (0.26 A) — so the same block works in 24 VDC control circuits and 230 VAC motor starter feedback loops without derating surprises.
Mounting and integration details
Snaps onto standard 35 mm DIN rail or screws directly to a panel backplate. The S00 footprint — 45 mm wide, 58 mm high, 73 mm deep — fits alongside S00 contactors in a compact row, with clearance requirements of 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side for heat dissipation and wiring access. Mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward or backward by +/-22.5° on a vertical mounting surface, which helps when fitting into tight enclosures or angled subpanels.
Wiring and termination
Terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid or stranded wire, plus AWG equivalents 2x (20 to 16), 2x (18 to 14), and 2x 12. Screw-type clamping, so strip length and torque matter — the 4 mm² capacity means you can loop through for daisy-chained commons without a separate terminal block.
Environmental and compliance notes
Rated for pollution degree 3 (conductive pollution or dry non-conductive pollution that becomes conductive due to condensation), which is typical for industrial control panels not in sealed clean rooms. Operating temperature range -25 to +60 °C, storage -55 to +80 °C. RoHS compliance date of October 1, 2009, covering substance restrictions.