The Siemens 3RH1122-2JC40-ZX95 is a SIRIUS coupling relay for switching auxiliary circuits, sized S00. It carries 2 NO instantaneous contacts and carries 10 A at 24 V rated value, with a 6 kV surge voltage resistance rating. The front is IP20, and it mounts via screw or snap-on to a DIN rail.
Ratings and what they mean for fit
The 10 A at 24 V rating tells you this relay handles the control-circuit loads typical in a 24 VDC panel — solenoids, contactor coils, indicator lamps. The 6 kV surge voltage resistance means it withstands the switching transients that appear when you break inductive loads in a mixed-voltage cabinet, so you don't get nuisance failure on the auxiliary contacts. The contact reliability spec — one incorrect switching operation per 100 million operations at 17 V, 1 mA — matters when this relay is used in low-energy signal paths, like a PLC input dry-contact chain. At that level, oxide films on standard contacts can block current; this part is designed to punch through. The solid conductor range is 2x (0.25 to 2.5 mm²), which covers standard control wiring in most panels. The depth of 73 mm and width of 45 mm fit the S00 footprint — common across SIRIUS contactors and relays, so it aligns with existing panel layouts.
Mounting and integration
Fastening is by screw or snap-on mounting. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward. Shock resistance is 10g / 5 ms and 5g / 10 ms, which covers most industrial panel applications including near conveyor drives and compressors. The built-in surge suppressor is a diode, so for DC coils the suppression polarity matters — verify your circuit's free-wheel diode orientation if you're paralleling this with other relay coils on the same DC bus.