{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-2FA11","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-2FA11","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-2FA11","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-2FA11","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RH1921-2FA11 auxiliary switch block, 1 NO + 1 NC, spring-loaded terminals, snap-on mounting for size S0...S12 contactors, 10 A at 24 V, IP20.","salesMarkdown":"It snaps onto contactor relays and power contactors in the S0 through S12 frame sizes, per the EN 50005 mounting standard. The 'with 3RT1' note on the line item indicates this block is designed to pair with the 3RT1 contactor family — it's the add-on contact module, not a standalone contactor. At 400 V the rating drops to 3 A, and at 690 V it's 1 A — the insulation voltage is rated 690 V with pollution degree 3, so this block can live in a standard industrial panel without extra creepage spacing. ## Physical Integration and Wiring Dimensions are 44 mm wide, 38 mm high, and 51 mm deep — it occupies the same width as the S0 contactor it mounts on. The spring-loaded terminals accept 2x 0.5 to 2.5 mm² without ferrules, or 2x 0.5 to 1.5 mm² with ferrules. AWG equivalents are 2x 20 to 14.","metaTitle":"Siemens SIRIUS 3RH1921-2FA11 Auxiliary Switch Block, 1 NO+1","metaDescription":"Siemens SIRIUS 3RH1921-2FA11 auxiliary switch block, 1 NO + 1 NC, spring-loaded terminals. Phased-out; successor is 3RH2 series. Snap-on for S0–S12 contactors. Rated 10 A at 24 V.","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","Maximum":"10 A","at 24 V":"6 A","at 60 V":"2 A","at 110 V":"1 A","at 125 V":"6 A","at 220 V":"0.3 A","at 230 V":"6 A","at 250 V":"6 A","at 400 V":"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","at 24 V rated value":"10 A","at 60 V rated value":"4.7 A","at 110 V rated value":"3 A","at 220 V rated value":"1.2 A","at 440 V rated value":"0.5 A","at 600 V rated value":"0.26 A","Instantaneous Contact":"1","With Core End Processing":"2x (0.5 ... 1.5 mm²)","Without Core End Processing":"2x (0.5 ... 2.5 mm²)","at AC-15 at 690 V rated value":"1 A","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":"10 000 000","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=266055&mlfb=3RH1921-2FA11","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-2FA11/alternatives.json"},"ai":{"faq":[{"question":"What does the 'with 3RT1' note mean?","answer":"It means this auxiliary switch block is intended for use with 3RT1 contactors. It snaps onto the contactor's front mounting slots and connects mechanically to the contactor's armature."},{"question":"What are the key ratings for the 3RH1921-2FA11?","answer":"Rated 10 A at 24 V AC-15, 3 A at 400 V, 1 A at 690 V. Mechanical life is 10 million cycles. Contact reliability is 1 fault per 100 million operations at 17 V, 1 mA. Surge voltage resistance is 6 kV. Operating temperature is -25 to +60 °C."},{"question":"Will the 3RH1921-2FA11 fit a panel designed for the 3RH2422-1AB00?","answer":"No. The 3RH2422-1AB00 is a different form factor (73 mm deep, 90 mm wide) with screw terminals and 2 NO + 2 NC contacts. The 3RH1921-2FA11 is 51 mm deep, 44 mm wide, with spring terminals and 1 NO + 1 NC. The mounting hole pattern and wiring scheme are incompatible without panel rework."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-2FA11","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/3RH1921-2FA11 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}}