{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU1146-4KB1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU1146-4KB1","canonicalUrl":"https://aoctrl.com/siemens/3RU1146-4KB1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU1146-4KB1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU1146-4KB1 thermal overload relay, CLASS 10, S3 size, screw terminals, IP20 front, ATEX certified.","salesMarkdown":"## Motor protection relay for screw-terminal panels The Siemens 3RU1146-4KB1 is a SIRIUS thermal overload relay — the part that sits between the contactor and the motor to protect against sustained overcurrent. Rated for screw-type terminals on both the main circuit and the auxiliary/control circuit — no crimp lugs or ring terminals needed for the power wiring. The S3 frame size accepts stranded conductors up to 70 mm² on the main poles. ## Trip class, coordination, and ATEX Short-circuit coordination is specified for both Type 1 and Type 2: with a gG fuse rated 250 A (Type 1) or 160 A (Type 2), the relay withstands fault currents without damage to the downstream contactor. Surge voltage resistance is 8 kV. Carries ATEX approval (DMT 98 ATEX G 001) for use in potentially explosive gas atmospheres — the relay can be part of a motor protection scheme in Zone 1 or Zone 2 areas when paired with an appropriate contactor and upstream protection. ## Panel fit and environmental tolerance Dimensions are 70 mm wide, 120 mm high, and 140 mm deep — the S3 footprint matches the SIRIUS 3RT2 contactor range for direct mounting. Stand-alone installation is standard, with the mounting surface vertical and rotatable ±135° or tiltable ±45° front/back. Rated for 100 % relative humidity during operation. Shock resistance is 8 g for 10 ms — suitable for machine-mounted panels on presses, conveyors, or compressors where vibration is present. ## Wiring and auxiliary contact ratings Auxiliary terminals accept AWG 20…16 and 18…14 (two wires per terminal). Power dissipation is 6.3 W per pole — account for this heat in the panel thermal budget, especially when multiple relays are ganged side-by-side. Minimum side clearance is 6 mm.","metaTitle":"Siemens 3RU1146-4KB1 SIRIUS Thermal Overload Relay, CLASS 10","metaDescription":"Siemens 3RU1146-4KB1 SIRIUS thermal overload relay, CLASS 10 trip, S3 size, IP20 front, ATEX certified. Active production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Depth":"140 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Width":"70 mm","title":"3RU1146-4KB1","Height":"120 mm","Upwards":"0 mm","at 24 V":"1 A","Forwards":"0 mm","Per Pole":"6.3 W","Stranded":"2x (10 ... 50 mm²), 10 ... 70 mm²","at 110 V":"0.22 A","at 120 V":"3 A","at 125 V":"0.22 A","at 220 V":"0.11 A","at 230 V":"2 A","at 400 V":"1 A","Backwards":"0 mm","Downwards":"0 mm","Trip Class":"CLASS 10","At The Side":"6 mm","description":"Overload relay 57...75 A For motor protection Size S3, Class 10 Stand-alone installation Main circuit: Screw terminal Auxiliary circuit: Screw terminal Manual-Automatic-Reset!!! Phased-out product!!! Successor is SIRIUS 3RU2 Preferred successor type is >>3RU2136-4RB1<<","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"stand-alone installation","Shock Resistance":"8g / 10 ms","Mounting Position":"with vertical mounting surface +/-135° rotatable, with vertical mounting surface +/- 45° tiltable to the front and back","Product Brand Name":"SIRIUS","Type Of Protection":"DMT 98 ATEX G 001","Product Designation":"thermal overload relay","Size Of Overload Relay":"S3","For Main Current Circuit":"screw-type terminals","Substance Prohibitance (Date)":"07/01/2006","protection class IP on the front":"IP20","For Auxiliary And Control Circuit":"screw-type terminals","Relative Humidity During Operation":"100 %","With Type Of Assignment 2 Required":"gG: 160 A","Surge Voltage Resistance Rated Value":"8 kV","With Type Of Coordination 1 Required":"gG: 250 A","for AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","reference code according to IEC 81346-2":"F","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Number Of Poles For Main Current Circuit":"3","Touch Protection Against Electrical Shock":"finger-safe","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","Size Of Contactor Can Be Combined Company-Specific":"S3","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 6 A, quick: 10 A","insulation voltage with degree of pollution 3 at AC rated value":"1 000 V","Product Component Removable Terminal For Auxiliary And Control Circuit":"No","power loss [W] for rated value of the current at AC in hot operating state":"18.9 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"57 ... 75 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/7a169fffd7e8871dabf242d8d7d0d408.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=501111&mlfb=3RU1146-4KB1"},"ai":{"faq":[{"question":"What is the closest functional second-source for 3RU1146-4KB1?","answer":"The peer MPNs listed (6ED1052-1MD08-0BA1, 6AG1052-2FB08-7BA1, 6ES7517-3FP00-0AB0) are not thermal overload relays — they belong to different product families (Siemens LOGO! and S7-1500). No direct drop-in replacement exists from those numbers. The 3RU1146-4KB1 is a SIRIUS S3 thermal overload relay; a functional equivalent would be another SIRIUS 3RU relay of the same size and trip class."},{"question":"What compliance documentation does Siemens provide for 3RU1146-4KB1?","answer":"The relay carries ATEX certification (DMT 98 ATEX G 001) for explosive atmospheres and is listed with a substance prohibitance date of 07/01/2006, indicating RoHS compliance."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU1146-4KB1","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/3RU1146-4KB1 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}}