{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2911-4HA21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2911-4HA21","canonicalUrl":"https://aoctrl.com/siemens/3RH2911-4HA21","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2911-4HA21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary switch, 3RH2911-4HA21, 2 N/O instantaneous contacts, snap-on front mounting for contactors size S00, S0, S2, S3, ring terminal lug connection.","salesMarkdown":"The Siemens 3RH2911-4HA21 is a SIRIUS auxiliary switch block designed to snap onto the front of contactors in sizes S00, S0, S2, and S3. It provides two normally open (N/O) instantaneous contacts, with no normally closed (N/C) or delayed contacts on this variant. The connection method is ring terminal lug, which means you'll need to crimp ring terminals onto your control wiring — no cage clamps or screw terminals here. The part is rated for AC-12 operational current up to 10 A and carries a mechanical service life of 10,000,000 operating cycles typical. Snap-on front mounting means this block clips directly onto the contactor's front face without tools. The footprint is 36 mm wide, 37.5 mm high, and 43.7 mm deep. ## Mirror contact and safety circuit use This auxiliary switch is listed as a mirror contact per IEC 60947-4-1 when used with 3RT2 contactors. That means the N/C contact position is mechanically linked to the main contact position — critical for safety circuits where you need to positively confirm the main contacts are open before allowing access or enabling a bypass. If your safety application requires mirror contacts, verify the mating contactor is a 3RT2 series. For BOM freeze or compliance documentation needs, the manufacturer provides standard SIRIUS-series declarations. This order code is the exact variant with ring terminal lugs and 2 N/O contacts — confirm your panel wiring practice accepts ring terminals before substituting a different terminal-style variant.","metaTitle":"Siemens 3RH2911-4HA21 SIRIUS Auxiliary Switch, 2 N/O + 0 N/C","metaDescription":"Siemens SIRIUS 3RH2911-4HA21 auxiliary switch for contactors S00-S3. Snap-on front mount, ring terminal connection. 2 instantaneous N/O contacts. Current production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"43.7 mm","Width":"36 mm","title":"3RH2911-4HA21","Height":"37.5 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","description":"auxiliary switch, on the front, 2 NO + 1 NC,.1/.2,.3/.4,.3/.4, --/--, current path: 1 NC, 1 NO, 1 NO, --, ring cable lug connection, 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","Product Category":"Auxiliary switch","Lagging Switching":"0","Size Of Contactor":"S00, S0, S2, S3","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","at 600 V rated value":"0.26 A","Design Of The Product":"for snapping onto the front","Instantaneous Contact":"2","Substance Prohibitance (Date)":"10/01/2009","protection class IP on the front":"IP00","Surge Voltage Resistance Rated Value":"6 kV","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 3RT2","operational current at AC-15 at 690 V rated value":"1 A","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":"ring terminal lug connection","insulation voltage with degree of pollution 3 at AC rated value":"690 V","number of CO contacts of auxiliary contacts instantaneous contact":"0"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/79885e4008d2057b560806a97bd36d93.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=401695&mlfb=3RH2911-4HA21"},"ai":{"faq":[{"question":"What contactor sizes does this auxiliary switch fit?","answer":"It fits SIRIUS contactors in sizes S00, S0, S2, and S3. The mounting method is snap-on front mounting."},{"question":"Does this auxiliary switch have mirror contacts for safety circuits?","answer":"Yes, it is listed as a mirror contact according to IEC 60947-4-1 when used with 3RT2 contactors. This provides positive mechanical linkage between the auxiliary N/C contact and the main contact position."},{"question":"What is the connection type for the control wiring?","answer":"The connection type is ring terminal lug. You will need to crimp ring terminals onto your control wires — it does not use cage clamps or screw terminals."},{"question":"What are the key dimensions of this auxiliary switch?","answer":"Width is 36 mm, height is 37.5 mm, and depth is 43.7 mm. The IP protection class on the front is IP00, so it requires installation inside a panel enclosure."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2911-4HA21","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/3RH2911-4HA21 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}}