{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-1FC22","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-1FC22","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-1FC22","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1FC22","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch block, 3RH1921-1FC22, 2 NO + 2 NC, screw terminals, snap-on mounting for Size S0 to S12 contactors, rated 10 A, IP20.","salesMarkdown":"The Siemens 3RH1921-1FC22 is a SIRIUS auxiliary switch block designed for contactor relays and power contactors in the Size S0 through S12 range. It provides 2 normally-open and 2 normally-closed contacts (2 NO + 2 NC) with screw-type terminals, and snaps onto the contactor without tools — a standard DIN-rail panel integration move. The block carries a maximum thermal current of 10 A. For DC-13 switching (solenoid loads), the rated current drops with voltage: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. These are the values that govern real-world fit — a 24 VDC solenoid circuit can pull the full 10 A, but a 220 VDC circuit is limited to 1.2 A. ## Lifecycle reality — phased out, successor available This part is a phased-out product. The official successor is the SIRIUS 3RH2 series. For new designs, migrate to the 3RH2 family to avoid future migration debt. Dimensions are 44 mm wide, 38 mm high, and 51 mm deep — compact enough for high-density panels. Surge voltage resistance is rated at 6 kV, and insulation voltage at 690 V AC with pollution degree 3. ## Wiring and contact reliability Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) conductors with core end processing, or 2x (20–16) and 2x (18–14) AWG. Mechanical service life is typically 10 million switching cycles.","metaTitle":"Siemens 3RH1921-1FC22 SIRIUS Auxiliary Switch Block, 2NO+2NC","metaDescription":"Siemens 3RH1921-1FC22 SIRIUS auxiliary switch block, 2 NO + 2 NC, 10 A rated, snap-on for Size S0–S12 contactors. Phased-out; successor 3RH2 series. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"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","Leading Contact":"2","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"snap-on mounting","Lagging Switching":"2","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":"0","With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 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 ... 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":"10 000 000","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=8820&mlfb=3RH1921-1FC22","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1FC22/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RH1921-1FC22?","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 are the key ratings of 3RH1921-1FC22?","answer":"Maximum thermal current is 10 A. DC-13 ratings: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, 0.26 A at 600 V. AC-15 rating is 1 A at 690 V. Mechanical life is 10 million cycles."},{"question":"Will 3RH1921-1FC22 drop into a panel specified for 3RT5056-8AP38-0PR0?","answer":"The 3RH1921-1FC22 is an auxiliary switch block for contactor sizes S0 through S12, while the 3RT5056-8AP38-0PR0 is a power contactor. They are not direct substitutes; the switch block mounts onto the contactor, not in place of it. Check the contactor's auxiliary slot compatibility before ordering."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-1FC22","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/3RH1921-1FC22 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}}