{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4NC1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4NC1","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4NC1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4NC1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU2126-4NC1 thermal overload relay, size S0, Trip Class 10, 15 kW at 400 V, 690 V rated, spring-loaded terminals, integrated auxiliary switch.","salesMarkdown":"The relay is rated for 15 kW at 400 V and 22 kW at 690 V (AC-3e duty), with a maximum rated insulation voltage of 690 V. The Trip Class 10 rating governs the thermal curve: it allows the motor to draw starting current for up to 10 seconds before the bimetallic strip trips. That suits motors that reach full speed within that window — standard squirrel-cage induction motors on centrifugal loads. For high-inertia loads (crushers, centrifuges) that need a longer acceleration ramp, a Class 20 or Class 30 relay would be required; this one will nuisance-trip on those. The power ratings are tied to specific voltages: 15 kW at 400 V, 18.5 kW at 500 V, and 22 kW at 690 V. The current ratings at 480 V and 600 V are both 28 A, which gives you the thermal setting range. The relay's rated insulation voltage is 690 V, so it can be used on 400 V, 480 V, 600 V, and 690 V systems without derating the insulation. The auxiliary switch is integrated — no separate add-on block needed. The switch ratings cover a wide control-voltage range: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V, among others. That means the same relay works in 24 VDC control circuits and 230 VAC panels without swapping the auxiliary contact block. Termination is spring-loaded (cage-clamp style), accepting 2× 0.5 to 2.5 mm² solid or stranded. No screw torque to verify — just strip to 8 mm and push in. The relay mounts in any position and is designed for stand-alone installation, not ganged to a contactor. The relay carries a substance prohibition date of October 1, 2009, aligning with RoHS and REACH substance restrictions. Temperature compensation is active from -40 to +60 °C, so the thermal curve stays accurate across the typical industrial panel ambient.","metaTitle":"Siemens 3RU2126-4NC1 SIRIUS thermal overload relay, S0, 15 k","metaDescription":"Siemens 3RU2126-4NC1 SIRIUS thermal overload relay, size S0, Trip Class 10, 15 kW at 400 V, 690 V rated, spring-loaded terminals. Current production. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"Tripped\"","Depth":"95 mm","Width":"45 mm","Height":"114 mm","at 24 V":"2 A","at 60 V":"0.3 A","Per Pole":"3.2 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":"stand-alone installation","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":"15 kW","at 480 V rated value":"28 A","at 500 V rated value":"18.5 kW","at 600 V rated value":"28 A","at 690 V rated value":"22 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":"28 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","operational current at AC-3e at 400 V rated value":"28 A","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":"9.6 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"23 ... 28 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/d9ee16c4ebf539204eb6579f75b7ad96.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=192894&mlfb=3RU2126-4NC1","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4NC1/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RU2126-4NC1 and how do I get a price?","answer":"This part is sourced to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead time."},{"question":"What is the closest functional alternative to 3RU2126-4NC1?","answer":"The 3RU2116-1FC1 is a smaller-frame SIRIUS overload relay (S00 size vs S0), so it will not physically fit the same contactor interface or mounting footprint. For a drop-in replacement without rewiring, stay with the S0 frame size in the 3RU2126 series."},{"question":"What does the note 'for message Tripped' mean on 3RU2126-4NC1?","answer":"The note indicates that the integrated auxiliary switch changes state to signal a 'Tripped' condition — it is the normally-closed contact that opens when the relay trips, providing a status signal to a PLC or indicator light."},{"question":"What is the depth of 3RU2126-4NC1?","answer":"The depth is 95 mm, with a width of 45 mm and height of 114 mm. This is the S0 frame size — it mounts on DIN rail or directly with screws."},{"question":"Will 3RU2126-4NC1 drop into a panel wired for 3RU2116-1FC1?","answer":"No — the 3RU2116-1FC1 is an S00 frame size with different mounting hole spacing and terminal layout. The S0 frame of the 3RU2126-4NC1 is physically larger and will not align with the existing footprint without panel modifications."},{"question":"What compliance documentation does Siemens provide for 3RU2126-4NC1?","answer":"The relay carries a substance prohibition date of October 1, 2009, indicating RoHS and REACH compliance. Standard Siemens documentation includes the declaration of conformity and environmental product declaration."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4NC1","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/3RU2126-4NC1 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}}