{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4CJ0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4CJ0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4CJ0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4CJ0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU2126-4CJ0 thermal overload relay, size S0, CLASS 10, contactor mounting, 690 V rated, 85 x 45 x 85 mm.","salesMarkdown":"Rated for 690 V, it handles motor loads up to 11 kW at 400 V and 18.5 kW at 690 V. The thermal bimetallic release is temperature-compensated from -40 to +60 °C, so the trip curve stays consistent whether the panel is in a cold warehouse or a hot machine room. Mounts directly onto a contactor via the contactor mounting fastening method — no DIN rail required, though the S0 footprint is standard for the SIRIUS family. Main circuit connections use ring cable lugs (M4 screw size), and the auxiliary switch is integrated. A Pozidriv PZ 2 screwdriver with a 5–6 mm shaft diameter is what you'll need for the terminals. The switching ratings across the voltage range tell you what auxiliary contacts can handle: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, 0.75 A at 690 V. These are for the integrated auxiliary switch, not the main motor circuit — the main path is rated for the full motor kW figures above. If you're using the auxiliary contact to signal a PLC input, check the voltage and current draw against these numbers. Trip class CLASS 10 is the key selection parameter: it matches standard squirrel-cage motor starting profiles. If your application has a long acceleration time (high-inertia loads like fans or flywheels), you'd typically step up to CLASS 20 or CLASS 30 — but for most conveyors, pumps, and compressors, CLASS 10 is the right call.","metaTitle":"Siemens 3RU2126-4CJ0 SIRIUS thermal overload relay, S0, CLAS","metaDescription":"Siemens 3RU2126-4CJ0 SIRIUS thermal overload relay, size S0, CLASS 10 trip. Rated 690 V, 11 kW at 400 V. Contactor mounting. Current production. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"Tripped\"","Depth":"85 mm","Width":"45 mm","title":"3RU2126-4CJ0","Height":"85 mm","at 24 V":"2 A","at 60 V":"0.3 A","Per Pole":"2.7 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","at 690 V":"0.75 A","Trip Class":"CLASS 10","Rated Value":"690 V","description":"Overload relay 17...22 A Thermal For motor protection Size S0, Class 10 Contactor mounting Main circuit: Ring cable lug Auxiliary circuit: ring cable lug Manual-Automatic-Reset","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-40 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"Contactor mounting","For Main Contacts":"M4","Mounting Position":"any","Product Brand Name":"SIRIUS","Product Designation":"thermal overload relay","at 400 V rated value":"11 kW","at 480 V rated value":"22 A","at 500 V rated value":"11 kW","at 600 V rated value":"22 A","at 690 V rated value":"18.5 kW","Size Of Overload Relay":"S0","For Main Current Circuit":"Ring cable lug connection","Temperature Compensation":"-40 ... +60 °C","MTTF with high demand rate":"2 280 a","Design Of Screwdriver Shaft":"Diameter 5 ... 6 mm","Size Of The Screwdriver Tip":"Pozidriv PZ 2","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":"22 A","For Auxiliary And Control Circuit":"ring terminal lug connection","Between Main And Auxiliary Circuit":"440 V","Relative Humidity During Operation":"10 ... 95 %","Display Version For Switching Status":"Slide switch","For Main Contacts For Ring Cable Lug":"2.5 ... 2 N·m","Surge Voltage Resistance Rated Value":"6 kV","Of The Auxiliary And Control Contacts":"M3","Between Auxiliary And Auxiliary Circuit":"440 V","reference code according to IEC 81346-2":"F","Number Of Poles For Main Current Circuit":"3","For Auxiliary Contacts For Ring Cable Lug":"0.8 ... 1.2 N·m","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","operational current at AC-3e at 400 V rated value":"22 A","Size Of Contactor Can Be Combined Company-Specific":"S0","Outer Diameter Of The Usable Ring Cable Lug Maximum":"7.5 mm","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":"8.1 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"17 ... 22 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/390956a3fd9f660dbcbae5ced3ce82a6.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=499618&mlfb=3RU2126-4CJ0"},"ai":{"faq":[{"question":"What does the note 'for message Tripped' mean?","answer":"The note indicates this thermal overload relay includes an integrated auxiliary contact that changes state when the relay trips, providing a 'tripped' signal — typically wired to a PLC input or indicator lamp for remote fault annunciation."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4CJ0","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/3RU2126-4CJ0 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}}