{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU1146-4KB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU1146-4KB0","canonicalUrl":"https://aoctrl.com/siemens/3RU1146-4KB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU1146-4KB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU1146-4KB0 thermal overload relay, S3 size, CLASS 10 trip class, contactor mounting, IP20 front, ATEX approved.","salesMarkdown":"## CLASS 10 trip curve and motor protection fit The 3RU1146-4KB0: That's the standard for standard-duty induction motors — pumps, fans, compressors — where the start time stays under 10 seconds. The S3 size matches SIRIUS contactors in the same frame class. Mounting is direct to the contactor — no DIN-rail bracket needed, which saves panel width and wiring labour. ## ATEX and coordination — what the approvals mean ATEX certification DMT 98 ATEX G 001 allows installation in gas-group explosive atmospheres (Zone 1 or Zone 2) when paired with an appropriate contactor and upstream protection. The relay itself is not the isolation device — it's the thermal sensing element inside the motor branch circuit. Short-circuit coordination is defined for gG fuses: Type 2 coordination requires 160 A fuses; Type 1 allows 250 A. This matters when designing selectivity downstream of a feeder breaker — the fuse size determines the let-through energy the relay must survive. Surge voltage withstand is 8 kV, which aligns with IEC 60947-1 overvoltage category III for industrial control panels. No additional surge suppression needed for standard 400 V networks. ## Panel fit and wiring constraints Dimensions are 140 mm deep, 70 mm wide, 120 mm tall. Main circuit terminals accept stranded copper from 10 mm² up to 70 mm² — covers motor leads up to about 160 A full load depending on cable type. Control-circuit terminals take solid 0.5–2.5 mm² or stranded equivalents. Mounting position is flexible: ±135° rotation and ±45° tilt from vertical. This helps when the contactor is mounted on a swing frame or in a tight cabinet where straight vertical isn't possible. ## Thermal load and ambient limits Each pole dissipates 6.3 W at rated current. For a three-pole relay that's 18.9 W total — modest, but add the contactor coil and the combined heat can push a small enclosure past its thermal limit if ventilation is poor. The 100 % relative humidity rating during operation means condensation is tolerated, but the IP20 front face does not protect against hose-down or dripping water — keep it inside the panel. ## Auxiliary contact ratings for control circuits These cover direct PLC inputs or small relay coils without an interposing relay in most 24 VDC or 120 VAC control schemes. At 110 V and 125 V DC the rating drops to 0.22 A; at 220 V DC it's 0.11 A. If the control circuit is DC and above 24 V, check the contact rating against the load — the DC break capacity is significantly lower than AC. ## Mechanical robustness for vibrating plant Shock resistance is 8g for 10 ms. That's adequate for most motor-driven machinery (conveyors, crushers, compressors) but not for high-impact applications like forging presses or drop hammers — those need a separate shock-mounted enclosure. ## Compliance documentation RoHS compliance is confirmed by the substance prohibitance date of 07/01/2006. The IEC 81346-2 reference code F designates the protection function in system schematics. ATEX documentation (DMT 98 ATEX G 001) is available from Siemens for the installation file.","metaTitle":"Siemens 3RU1146-4KB0 SIRIUS thermal overload relay, CLASS 10","metaDescription":"Siemens 3RU1146-4KB0 SIRIUS thermal overload relay, S3 size, CLASS 10, contactor mounting, ATEX approved. 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":"3RU1146-4KB0","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 Contactor mounting Main circuit: Screw terminal Auxiliary circuit: Screw terminal Manual-Automatic-Reset!!! Phased-out product!!! Successor is SIRIUS 3RU2 Preferred successor type is >>3RU2136-4RB0<<","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"Contactor mounting","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","at 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":"$203.84","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/f1a1d6a17fcde18c03682e7e0ec0e7ab.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=444715&mlfb=3RU1146-4KB0"},"ai":{"faq":[{"question":"What compliance documentation does Siemens provide for 3RU1146-4KB0?","answer":"The relay carries ATEX certification DMT 98 ATEX G 001 for gas atmospheres, RoHS compliance per the July 2006 substance prohibitance date, and a reference code F per IEC 81346-2 for protection function designation. The manufacturer provides the ATEX certificate and declaration of conformity with the product documentation."},{"question":"What wire sizes does the 3RU1146-4KB0 accept?","answer":"Main circuit terminals accept stranded copper from 10 mm² up to 70 mm²."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU1146-4KB0","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/3RU1146-4KB0 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}}