{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2911-2HA21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2911-2HA21","canonicalUrl":"https://aoctrl.com/siemens/3RH2911-2HA21","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2911-2HA21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RH2911-2HA21 auxiliary switch block, 2 NO + 1 NC contacts, 10 A maximum, spring-loaded terminals, snap-on DIN rail mounting, IP20 front protection.","salesMarkdown":"## Contact configuration and what it means for your control circuit The 3RH2911-2HA21: This auxiliary switch block mounts on the front of Siemens 3RT2 contactors and 3RH2 contactor relays, adding 2 normally-open and 1 normally-closed auxiliary contacts to the switching device. The contact arrangement is 1 NC + 1 NO + 1 NO across three current paths, giving you one break-before-make pair and one independent make contact — enough to interlock a reversing starter or signal a PLC input while the main power path stays separate. ## Rated currents across the voltage range — the AC-15 duty curve The maximum thermal current is 10 A, but the switching capacity depends on the operating voltage and load type. At 24 V AC-15 (solenoid/contactor coil duty) the contacts are rated 10 A; at 110 V the rating drops to 3 A, and at 220 V it falls to 1.2 A. For DC switching the derating is steeper: 6 A at 24 V DC, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V. The DC arc extinguishes slower than AC, so the contact gap and material limit the interrupting capacity — this matters when the auxiliary switch controls a DC brake coil or a DC-powered indicator. At 690 V AC-15 the rated current is 1 A, and the rated insulation voltage is 690 V with pollution degree 3 — the contacts can live on a 480/277 V panel bus without derating for altitude or contamination. ## Termination and mounting — spring-loaded terminals on a snap-on footprint The auxiliary and control circuit connections use spring-loaded terminals — no screw torque to verify, no periodic re-torquing on a vibrating panel. Each terminal accepts two conductors: 0.5 to 1.5 mm² with ferrule, or 0.5 to 2.5 mm² without ferrule (20 to 14 AWG). Mounting is snap-on DIN rail (35 mm). The block is 36 mm wide, 47.7 mm deep, and 41.5 mm tall — it adds about 36 mm to the width of the base contactor or relay, so plan the DIN rail layout accordingly. ## Lifecycle and sourcing — current production, quoted to order It is part of the Siemens SIRIUS family, which is an active product portfolio with broad installed base. ## Contact reliability and mechanical endurance The mechanical service life is 10 million switching cycles typical — the spring-loaded terminal block and the snap-on latch will outlast most panel rebuild cycles. Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA, which covers dry-circuit PLC input signals where oxide films on silver contacts can cause intermittent opens. Surge voltage resistance is 6 kV, and the operating temperature range is -25 to +60 °C with storage from -55 to +80 °C — suitable for unheated electrical rooms and outdoor-rated enclosures within the IP20 front protection limit.","metaTitle":"Siemens 3RH2911-2HA21 SIRIUS Auxiliary Switch, 10 A","metaDescription":"Siemens 3RH2911-2HA21 SIRIUS auxiliary switch block, 2 NO + 1 NC contacts, rated 10 A at 24 V AC-15. Spring-loaded terminals, snap-on DIN rail mount.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Contactors"],"specifications":{"Note":"with 3RH2","Depth":"47.7 mm","Width":"36 mm","title":"3RH2911-2HA21","Height":"41.5 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","description":"auxiliary switch, on the front, 2 NO + 1 NC,.1/.2,.3/.4,.3/.4, --/--, current path: 1 NC, 1 NO, 1 NO, --, spring-loaded terminal, for contactors 3RT2 and contactor relays 3RH2","During Storage":"-55 ... +80 °C","Leading Contact":"0","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"snap-on mounting","Lagging Switching":"0","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":"2","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":"$5.27","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/1e3e5e16fdce6097568af7505a320125.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=272410&mlfb=3RH2911-2HA21"},"ai":{"faq":[{"question":"What is the 3RH2911-2HA21 used for?","answer":"It is a front-mounted auxiliary switch block for Siemens 3RT2 contactors and 3RH2 contactor relays, adding 2 NO + 1 NC auxiliary contacts for control circuit interlocking, status feedback, or PLC input signalling."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2911-2HA21","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/3RH2911-2HA21 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}