{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH2911-4FB11","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH2911-4FB11","canonicalUrl":"https://aoctrl.com/siemens/3RH2911-4FB11","factsUrl":"https://aoctrl.com/api/mcp/products/3RH2911-4FB11","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RH2911-4FB11 auxiliary switch, 1 NO + 1 NC contacts, snap-on front mounting for contactor sizes S00, S0, S2, S3, rated 10 A AC-12, 6 kV surge voltage resistance.","salesMarkdown":"## What this auxiliary switch does in a panel The 3RH2911-4FB11 is a SIRIUS auxiliary switch block designed to snap onto the front of Siemens contactor relays and power contactors in frame sizes S00, S0, S2, and S3 — it adds one normally-open and one normally-closed auxiliary contact to the base device without extra wiring or panel space. Mounting is tool-free: the block snaps onto the contactor front face, and the connection uses ring terminal lugs — no push-in or screw-cage terminals, so factor in a crimp tool and ring terminals for the control wiring. The auxiliary contacts are rated for a mechanical service life of 10 million operating cycles typical, with a contact reliability of one faulty switching per 100 million operations at 17 V, 1 mA — that low-level spec matters for PLC inputs that sink milliamps through dry contacts. ## Switching ratings — what the numbers mean The contact block carries a maximum operational current of 10 A at AC-12 (resistive loads), but the actual switching capacity depends on the voltage and duty: at 24 V it switches 6 A (AC-15) or 10 A (rated value), while at 230 V it handles 6 A AC-15 and at 400 V it switches 3 A — the voltage derating is steep above 230 V. For inductive loads in AC-15 duty at 690 V, the rated operational current is 1 A — this is the figure to use for contactor coil feedback or valve solenoids on a 690 V line. The DC switching capability covers 24 V at 10 A, 60 V at 4.7 A, 110 V at 3 A, 220 V at 1.2 A, and 600 V at 0.26 A — the rapid derating above 110 V means this block is best suited for 24 VDC control circuits unless the load is very light. Surge voltage resistance is rated at 6 kV, which covers most industrial control panel transient environments without additional snubbers. ## Lifecycle and sourcing reality The IP00 front protection rating means this block is intended for installation inside a closed panel — not for washdown or outdoor exposed mounting without an additional enclosure. RoHS compliance is documented with a substance prohibition date of October 1, 2009; the part does not carry mirror contact functionality per IEC 60947-4-1, so it is not suitable for applications requiring mirrored auxiliary contacts for safety feedback. ## Panel fit — dimensions and integration The block measures 36 mm wide, 37.5 mm high, and 43.7 mm deep — it adds negligible depth to the contactor stack and fits within the standard S00/S0/S2/S3 footprint without encroaching on adjacent devices. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C — adequate for most indoor industrial environments but verify ambient near ovens or foundry lines.","metaTitle":"Siemens 3RH2911-4FB11 SIRIUS Auxiliary Switch, 10 A max","metaDescription":"Siemens 3RH2911-4FB11 SIRIUS auxiliary switch for contactor relays S00-S3. Snap-on front mount, 1 NO + 1 NC, rated 10 A AC-12, 6 kV surge.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"43.7 mm","Width":"36 mm","title":"3RH2911-4FB11","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, 1 NO + 1 NC, 11 U,.7/.8, --/--,.5/.6, --/--, current path: 1 NO (leading), --, 1 NC (lagging), --, ring cable lug connection, for contactors 3RT2 and contactor relays 3RH2","During Storage":"-55 ... +80 °C","Leading Contact":"1","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"snap-on mounting","Product Category":"Auxiliary switch","Lagging Switching":"1","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":"0","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":"No","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/7686c613c6915909df9a2947ba571b59.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=55754&mlfb=3RH2911-4FB11"},"ai":{"faq":[{"question":"What contactor sizes does the 3RH2911-4FB11 fit?","answer":"It snaps onto the front of SIRIUS contactor relays and power contactors in frame sizes S00, S0, S2, and S3 — the same auxiliary switch block covers the entire small-to-mid contactor range."},{"question":"What are the key switching ratings for the 3RH2911-4FB11?","answer":"The auxiliary contacts are rated 10 A maximum at AC-12 (resistive), 6 A at 24 V AC-15, 6 A at 230 V AC-15, and 3 A at 400 V AC-15. For DC, the rated values are 10 A at 24 V, 3 A at 110 V, and 0.26 A at 600 V. The AC-15 rating at 690 V is 1 A."},{"question":"Does the 3RH2911-4FB11 have mirror contacts for safety applications?","answer":"No — the mirror contact per IEC 60947-4-1 is not supported. This auxiliary switch block is not suitable for safety-related feedback circuits that require mirrored contact behavior."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH2911-4FB11","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/3RH2911-4FB11 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}}