SIRIUS auxiliary contactor, size S00 — 3 NO, 10 A
The Siemens 3RH1131-1BE40 is a SIRIUS auxiliary contactor in size S00, providing three normally-open (3 NO) instantaneous contacts for control-circuit switching. It snaps onto a DIN rail or screws directly to a mounting plate, with a 45 mm width that fits standard panel layout grids and a 57.5 mm height that clears typical enclosure depths. Rated at 10 A at 24 V (AC-12 maximum 10 A), it handles pilot-duty loads, PLC outputs, and relay coils within a control cabinet. The 6 kV surge voltage resistance gives it a solid margin for industrial environments with switching transients.
Wire termination and panel fit
Terminals accept solid conductors: 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), or 2x 4 mm² per clamp. Spring-cage or screw terminals? The spec shows solid wire only — use ferruled stranded at the larger cross-sections to avoid whisker issues. Depth of 72 mm leaves clearance for wiring ducts and gland plates in shallow enclosures. Mounting position is flexible: ±180° rotation on a vertical surface, plus ±22.5° tilt forward/backward. The IP20 front protection means it's intended for enclosed panels, not open washdown areas.
Switching capacity across voltages
The 3RH1131-1BE40's contact ratings drop with voltage: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. For a 110 V control circuit it delivers 1 A; at 220 V it's 0.27 A. This derating curve follows the AC-12 resistive load profile — don't assume the 10 A holds at higher voltages.