{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-1JA11","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-1JA11","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-1JA11","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1JA11","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch, S0 size, 1 N/O contact, screw terminals, snap-on mounting, 10 A AC-12, IP20 front.","salesMarkdown":"It adds one N/O mirror contact to the contactor or contactor relay, giving you a mechanically linked, positively driven auxiliary that signals the main contact position without relying on the coil state. The mirror contact meets IEC 60947-4-1 when used with a 3RT1 contactor, which means it's suitable for safety circuits where you need to verify the main contacts are open before allowing access or enabling a downstream device. ## Switching capacity — what the voltage columns tell you This switch carries two sets of current ratings because the contact performance changes with the load type. For the heavier AC-15 / DC switching duty typical of contactor coils, solenoid valves, and small motors, the ratings are lower: 6 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V and 250 V, and 3 A at 400 V. The AC-12 number is your maximum continuous current; the AC-15 column governs the inrush when switching inductive loads. ## Mounting and wiring in the panel The 10 mm width means it adds minimal rail space; you can stack a second unit laterally if you need more auxiliary contacts. Screw-type terminals accept two conductors per clamp: solid or stranded from 0.5 to 2.5 mm² (AWG 20 to 14), or finely stranded with ferrules in the same range. Strip length is standard at 8–10 mm.","metaTitle":"Siemens SIRIUS 3RH1921-1JA11 Auxiliary Switch, S0, 10 A AC-1","metaDescription":"Siemens SIRIUS 3RH1921-1JA11 auxiliary switch for S0 contactors. 10 A AC-12, 6 kV surge, IP20, snap-on DIN rail. Current production, quoted to order. Request RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Depth":"71 mm","Width":"10 mm","Height":"80 mm","at 24 V":"6 A","at 48 V":"2 A","at 60 V":"2 A","at 110 V":"1 A","at 125 V":"0.9 A","at 220 V":"0.3 A","at 230 V":"6 A","at 250 V":"0.3 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 Category":"Auxiliary switch","Size Of Contactor":"S0","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"auxiliary switch","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","Design Of The Product":"second can be mounted laterally","Instantaneous Contact":"1","Substance Prohibitance (Date)":"07/01/2006","protection class IP on the front":"IP20","Surge Voltage Resistance Rated Value":"6 kV","for AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","mirror contact according to IEC 60947-4-1":"Yes; with 3RT1","Mechanical Service Life (Operating Cycles) Typical":"10 000 000","operational current of auxiliary contacts at AC-12 maximum":"10 A","Type Of Electrical Connection For Auxiliary And Control Circuit":"screw-type terminals","insulation voltage with degree of pollution 3 at AC rated value":"500 V","number of CO contacts of auxiliary contacts instantaneous contact":"0","AWG number as coded connectable conductor cross section for auxiliary contacts":"20 ... 14"}},"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=440900&mlfb=3RH1921-1JA11","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1JA11/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RH1921-1JA11 and what is the lead time?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"What is the width of 3RH1921-1JA11?","answer":"The width is 10 mm, which matches the standard S0 contactor width and keeps the assembly compact on the DIN rail."},{"question":"Will 3RH1921-1JA11 drop into a panel specified around 3RH2122-1BA40?","answer":"Both are SIRIUS auxiliary switches for the S0 frame with the same 10 mm width and snap-on DIN mounting, so the mechanical fit is identical. The 3RH2122-1BA40 carries two N/O contacts; this one carries one N/O mirror contact. Wiring differences depend on how many auxiliary contacts your circuit needs."},{"question":"What compliance documentation does Siemens provide for 3RH1921-1JA11?","answer":"The part carries RoHS compliance with a substance prohibition date of July 1, 2006. It is designed to meet IEC 60947-4-1 for mirror contact functionality and is rated for 6 kV surge voltage withstand with 500 V insulation at pollution degree 3."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-1JA11","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/3RH1921-1JA11 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}}