{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-1LA02","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-1LA02","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-1LA02","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1LA02","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch block, 3RH1921-1LA02, 2 NC, screw terminals, 10 A max, for 3RT1 contactors.","salesMarkdown":"It carries a maximum thermal current of 10 A and is rated for AC-15 and DC-13 switching duties across a range of control voltages: 6 A at 24 V, 6 A at 125 V, 6 A at 230 V, and 3 A at 400 V, among others. The screw-type terminals accept 2x (0.5…1.5 mm²) or 2x (0.75…2.5 mm²) with core-end processing, or 2x (20…16) and 2x (18…14) AWG. Snap-on mounting onto the contactor body — no DIN rail required for the block itself, though the base contactor typically mounts on a 35 mm rail. The block adds 44 mm width, 38 mm height, and 51 mm depth to the assembly. Front-side IP20 protection means it is safe for finger contact inside an enclosed panel but not for exposed washdown areas. The AC-15 ratings (6 A at 230 V, 3 A at 400 V, 1 A at 690 V) govern solenoid and contactor coil switching — the most common load for an auxiliary block. The 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) cover DC electromagnet loads with a time constant. If your control circuit operates at 24 VDC and pulls more than 10 A inrush, this block is not a fit.","metaTitle":"Siemens 3RH1921-1LA02 Auxiliary Switch Block, 2 NC, 10 A, SI","metaDescription":"Siemens SIRIUS 3RH1921-1LA02 auxiliary switch block, 2 NC contacts, 10 A max, screw terminals, snap-on for 3RT1 contactors. Phased-out; successor 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","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":"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=48370&mlfb=3RH1921-1LA02","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1LA02/alternatives.json"},"ai":{"faq":[{"question":"Will 3RH1921-1LA02 drop into a panel specified around 3RH2422-1AB00 without rewiring?","answer":"Not directly. The 3RH2422-1AB00 is a standalone auxiliary contactor with its own coil (AC-operated, 24 V, 50/60 Hz) and a different footprint (90 mm wide vs 44 mm for the switch block). The 3RH1921-1LA02 is a snap-on block for a 3RT1 base contactor, not a self-contained contactor. If the panel is wired for a 3RH2422-1AB00, you would need to re-engineer the mounting and control circuit."},{"question":"What does the note 'with 3RT1' mean?","answer":"It means this auxiliary switch block is designed to mount directly onto 3RT1 series contactors and contactor relays. It is not a standalone device."},{"question":"What is the depth of 3RH1921-1LA02?","answer":"51 mm, measured from the mounting face of the contactor."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-1LA02","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/3RH1921-1LA02 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}}