{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-2FE22-ZX95","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-2FE22-ZX95","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-2FE22-ZX95","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-2FE22-ZX95","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch block, 3RH1921-2FE22-ZX95, spring-loaded terminals, 1 NO + 1 NC encapsulated + 1 NO + 1 NC non-encapsulated, IP20, 690 V insulation, snap-on mounting.","salesMarkdown":"The Siemens SIRIUS 3RH1921-2FE22-ZX95 is a solid-state-compatible auxiliary switch block designed to mount on SIRIUS contactors and contactor relays in the S0 through S12 frame sizes. It provides two normally-open and two normally-closed auxiliary contacts — one set encapsulated, one set non-encapsulated — wired via spring-loaded terminals that accept 0.5 to 2.5 mm² stranded or 0.5 to 1.5 mm² with ferrule, or 20 to 14 AWG. The mechanical service life of 5 million switching cycles is typical for a SIRIUS auxiliary block — adequate for most machine cycles but worth noting if the application demands 10+ million operations (the successor 3RH2 series offers the same figure). The compact footprint — 44 mm wide, 38 mm high, 51 mm deep — fits standard DIN-rail spacing and leaves room for adjacent devices. ## Integration note: mounting on 3RT1 contactors The evidence explicitly notes this block is intended for use with 3RT1 contactors. It mounts on the front of the contactor, adding auxiliary contacts without increasing the panel width. The spring-loaded terminals eliminate the need for screwdriver torque checks during commissioning — strip to 8 mm, insert, and the cage clamps automatically. For a panel builder wiring a row of SIRIUS contactors, this block clips on after the contactor is DIN-rail mounted and wired.","metaTitle":"Siemens 3RH1921-2FE22-ZX95 SIRIUS auxiliary switch, 1 NO + 1","metaDescription":"Siemens SIRIUS 3RH1921-2FE22-ZX95 auxiliary switch block, spring-loaded terminals, 1 NO + 1 NC, IP20, 690 V insulation. Phased-out; successor is 3RH2 series. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Note":"with 3RT1","Depth":"51 mm","Width":"44 mm","Height":"38 mm","at 24 V":"0.3 A","at 60 V":"0.3 A","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"snap-on mounting","Product Brand Name":"SIRIUS","Suitability For Use":"Contactor relay and power contactor","Instantaneous Contact":"2","With Core End Processing":"2x (0.5 ... 1.5 mm²)","Without Core End Processing":"2x (0.5 ... 2.5 mm²)","protection class IP on the front":"IP20","Surge Voltage Resistance Rated Value":"6 kV","at AWG cables for auxiliary contacts":"2x (20 ... 14)","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","Mechanical Service Life (Switching Cycles) Typical":"5 000 000","Type Of Electrical Connection For Auxiliary And Control Circuit":"spring-loaded terminals","insulation voltage with degree of pollution 3 at AC rated value":"690 V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=311298&mlfb=3RH1921-2FE22-ZX95","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-2FE22-ZX95/alternatives.json"},"ai":{"faq":[{"question":"What replaces the 3RH1921-2FE22-ZX95?","answer":"The official successor is the SIRIUS 3RH2 series auxiliary switch block. That series uses a different housing and terminal layout, so a panel originally wired for the 3RH1921 may require terminal re-assignment or a different mounting adapter."},{"question":"What is the note 'with 3RT1' on this part?","answer":"It means this auxiliary switch block is designed to mount on SIRIUS 3RT1 power contactors. It is not a standalone device; it requires a 3RT1 contactor as the base."},{"question":"What are the terminal specifications?","answer":"Spring-loaded terminals accept 2x 0.5 to 2.5 mm² without ferrule, 2x 0.5 to 1.5 mm² with ferrule, or 2x 20 to 14 AWG. No screwdriver is needed for termination."},{"question":"Will the 3RH1921-2FE22-ZX95 fit a panel designed for the 3RH2422-1AB00?","answer":"No. The 3RH2422-1AB00 is a screw-terminal auxiliary contactor with different dimensions (73 mm depth, 90 mm width) and a different mounting footprint. The 3RH1921 is a snap-on auxiliary block for 3RT1 contactors, not a standalone contactor. They are not form-fit interchangeable."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-2FE22-ZX95","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/3RH1921-2FE22-ZX95 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}