{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-1FE31","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-1FE31","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-1FE31","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1FE31","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch block, 3RH1921-1FE31, 2 NO encapsulated + 1 NO+1 NC, snap-on mounting for 3RT1 contactors, screw terminals, IP20 front, 0.3 A at 24 V / 60 V.","salesMarkdown":"It provides three instantaneous contacts: two normally open (encapsulated) and one normally open plus one normally closed (not encapsulated). Rated at 0.3 A at both 24 V and 60 V, this block handles low-current signaling and control loads common in auxiliary circuits. The screw-type terminals accept solid or stranded wire: 2x (0.5 to 1.5 mm²) and 2x (0.75 to 2.5 mm²), or AWG equivalents 2x (20 to 16) and 2x (18 to 14). Mechanical service life is 5 million switching cycles typical. ## Panel Integration Dimensions: 44 mm wide, 38 mm high, 51 mm deep — fits within the standard S0 to S12 contactor envelope. No additional wiring harness or adapter needed; the screw terminals match the existing control-circuit wiring practice.","metaTitle":"Siemens 3RH1921-1FE31 SIRIUS Auxiliary Switch Block, 2 NO en","metaDescription":"Siemens 3RH1921-1FE31 SIRIUS auxiliary switch block for 3RT1 contactors. 2 NO (encapsulated) + 1 NO+1 NC, snap-on mounting, 0.3 A at 24 V. Phased out; successor 3RH2 series availab","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":"3","With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 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 ... 16), 2x (18 ... 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":"screw-type 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=424057&mlfb=3RH1921-1FE31","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1FE31/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RH1921-1FE31?","answer":"We source and quote this part to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"What does the note 'with 3RT1' mean on this part?","answer":"The note indicates this auxiliary switch block is designed for use with Siemens 3RT1 contactor relays and power contactors — it mounts directly on them."},{"question":"What compliance documentation is available for 3RH1921-1FE31?","answer":"The part carries SIRIUS brand documentation including RoHS and REACH declarations. Specific UL, IEC, or other certification details should be verified against the manufacturer's current documentation package."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-1FE31","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/3RH1921-1FE31 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}}