The Siemens 3RH1131-1AP00 is a SIRIUS auxiliary contactor in size S00, carrying 3 normally open instantaneous contacts. It's the signal-switching half of a motor starter or a standalone interposing relay — rated 10 A at 24 V for pilot-duty loads, derating to 1 A at 690 V for higher-voltage control circuits. Coil pulls in on 50 Hz (0.8...1.1) or 60 Hz (0.85...1.1) at 230 V. That 72 mm depth and 45 mm width mean it fits a standard DIN-rail footprint without crowding the gland plate; the screw-and-snap-on fastening lets a panel builder land it without reaching for a tool on every unit.
What the ratings mean for fit
Three NO contacts, no NC — that's the contact configuration on this block. If your BOM calls for a break contact, this isn't the variant; you'd need a 3RH1 with a different contact arrangement. The 10 A at 24 V is the thermal current for DC pilot duty; at 230 V AC it's 6 A, at 400 V it's 3 A. That's enough for a contactor coil or a small PLC output, not for power switching. Pollution degree 3 means it's rated for industrial environments where conductive dust or condensation can occur — no derating needed in a typical panel. Wire capacity runs 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), or 2x 4 mm² solid — that's two conductors per terminal for daisy-chaining. The spring-cage variant (3RH6131-1AP00) uses the same footprint but changes the termination method; if your panel spec calls for spring terminals, the screw-clamp here won't match without rewiring.
Lifecycle and sourcing reality
The SIRIUS platform is Siemens' standard control gear line, so documentation (CE, UKCA, RoHS date 01.07.2006) is readily available. The reference code per IEC 81346-2 is K — auxiliary contactor function in the naming standard.
Panel integration notes
Mounts on DIN rail via the screw-and-snap-on method — the screw provides vibration resistance, the snap-on gives quick placement. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so it fits tight enclosures without forcing the wiring. Shock rated at 10g / 5 ms and 5g / 10 ms, which covers most industrial panel vibration. IP20 on the front means finger-safe but not washdown; keep it inside a sealed enclosure.