{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-1KC0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-1KC0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-1KC0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-1KC0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU2126-1KC0, CLASS 10, S0 size, 690 V rated, spring-loaded terminals, 45 x 102 x 84 mm.","salesMarkdown":"It's the overcurrent protection element you mount directly onto a contactor — the part that watches motor current and trips when the load stays high too long. The integrated auxiliary switch signals the tripped state back to the PLC or annunciator. ## Trip Class and What It Decides That's the standard for standard-duty motor starting — pumps, fans, compressors that accelerate unloaded. If you're protecting a high-inertia load (centrifuge, flywheel) that needs a longer acceleration ramp, CLASS 10 is too fast; you'd want CLASS 20 or 30. For most general-purpose three-phase motors on 50/60 Hz supply, CLASS 10 is the correct call. S0 frame size, 45 mm wide, 102 mm tall, 84 mm deep. Fastens directly to the contactor — no DIN rail required, no extra bracketry. Spring-loaded terminals on the main circuit accept 2x (0.5... 2.5 mm²) solid or stranded. The screwdriver tip needed is 3.0 x 0.5 mm, shaft diameter 3 mm — keep that driver in the panel kit. ## Environmental Reach That's a part that survives the ride in an unheated truck and still works when you power it up at site. Current production.","metaTitle":"Siemens 3RU2126-1KC0 SIRIUS Thermal Overload Relay, CLASS 10","metaDescription":"Siemens 3RU2126-1KC0 SIRIUS thermal overload relay, CLASS 10 trip, S0 frame, 690V rated. Active production. Sourced to order. Quoted on request.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"Tripped\"","Depth":"84 mm","Width":"45 mm","Height":"102 mm","at 24 V":"2 A","at 60 V":"0.3 A","Per Pole":"2.2 W","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","Trip Class":"CLASS 10","Rated Value":"690 V","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-40 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"Contactor mounting","Mounting Position":"any","Solid Or Stranded":"2x (0.5 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"thermal overload relay","at 400 V rated value":"5.5 kW","at 480 V rated value":"12.5 A","at 500 V rated value":"7.5 kW","at 600 V rated value":"12.5 A","at 690 V rated value":"7.5 kW","Size Of Overload Relay":"S0","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-40 ... +60 °C","MTTF with high demand rate":"2 280 y","Design Of Screwdriver Shaft":"Diameter 3 mm","Size Of The Screwdriver Tip":"3,0 x 0,5 mm","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","Design Of The Auxiliary Switch":"integrated","Design Of The Overload Release":"thermal","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"12.5 A","at AWG cables for main contacts":"1x (18 ... 8)","For Auxiliary And Control Circuit":"spring-loaded terminals","Between Main And Auxiliary Circuit":"440 V","Relative Humidity During Operation":"10 ... 95 %","Display Version For Switching Status":"Slide switch","Surge Voltage Resistance Rated Value":"6 kV","at AWG cables for auxiliary contacts":"2x (20 ... 14)","Between Auxiliary And Auxiliary Circuit":"440 V","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","Finely Stranded Without Core End Processing":"2x (0.5 ... 1.5 mm²)","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","shock resistance according to IEC 60068-2-27":"8g / 11 ms","Size Of Contactor Can Be Combined Company-Specific":"S0","contact rating of auxiliary contacts according to UL":"B600 / R300","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gG: 6 A, quick: 10 A","insulation voltage with degree of pollution 3 at AC rated value":"690 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":"6.6 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"9 ... 12.5 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/58c7dbade6be9aa590eecc55ad84a967.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=151015&mlfb=3RU2126-1KC0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-1KC0/alternatives.json"},"ai":{"faq":[{"question":"What does the 'for message Tripped' note mean?","answer":"The integrated auxiliary switch changes state when the relay trips, and that signal is labeled 'Tripped' in the control circuit — it's the dry-contact feedback that tells the PLC or HMI the overload has operated."},{"question":"Will 3RU2126-1KC0 drop into a panel specified around 3RU2116-1FC1?","answer":"Both are S0-frame SIRIUS thermal overload relays with the same mounting pattern and spring-loaded terminal design. They share the same footprint and contactor interface, so no rewiring of the main circuit should be needed. Verify the auxiliary contact configuration matches your control schematic."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-1KC0","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/3RU2126-1KC0 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}