{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4EJ0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4EJ0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4EJ0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4EJ0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS, thermal overload relay, 3RU2126-4EJ0, size S0, Class 10, 32 A at 480/600 V, contactor mounting.","salesMarkdown":"It's designed to bolt directly onto a matching contactor, saving DIN-rail space and keeping the motor branch circuit compact. At 480 V or 600 V it carries a full-load motor current of 32 A, which corresponds to 15 kW at 400 V and 18.5 kW at 500 V — a common range for small-to-medium fixed-speed pumps, fans, and compressors. That's the standard for standard motors with normal starting times — a pump that spins up in a couple seconds is fine; a high-inertia fan that takes 15 seconds to accelerate will nuisance-trip on a Class 10. If you've got a long-start load, you'd need a Class 20 or 30 relay instead. The 32 A rating at 480 V and 600 V tells you the heater element is sized for that full-load current point. The relay accepts a range of current settings below that maximum, so you dial it to the motor nameplate FLA. The 15 kW / 18.5 kW / 30 kW power ratings at 400 V, 500 V, and 690 V respectively are the motor power the relay can protect at those line voltages — match the motor's rated voltage and power, not just the current. The auxiliary contact is integrated — no separate add-on block needed for the trip-indication or status feedback to the PLC. The Note 'for message Tripped' on the nameplate means the relay has a visual flag and a separate N/C contact that opens when the bimetals trip, so the control system sees the fault even if the contactor coil drops out. It mounts directly onto the contactor via the Fastening Method 'Contactor mounting', so no DIN rail bracket is needed underneath; the whole assembly clips onto the rail as one unit. The main circuit connection uses ring cable lugs, with M4 screw terminals sized for a Pozidriv PZ2 bit. Temperature compensation is active from -40 to +60 °C, so the trip curve stays accurate in a hot panel or a cold enclosure. The 3.2 W dissipation per pole at full load adds up — three poles at 9.6 W total — so if you're packing multiple contactor/relay pairs in a sealed cabinet, factor that heat into the ventilation calc.","metaTitle":"Siemens 3RU2126-4EJ0 SIRIUS Thermal Overload Relay, Class 10","metaDescription":"Siemens SIRIUS 3RU2126-4EJ0 thermal overload relay, Class 10, 32 A at 480/600 V. Active production. S0 size, contactor-mount. Available to order. Specifications and sourcing info.","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","Height":"85 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","at 690 V":"0.75 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","For Main Contacts":"M4","Mounting Position":"any","Product Brand Name":"SIRIUS","Product Designation":"thermal overload relay","at 400 V rated value":"15 kW","at 480 V rated value":"32 A","at 500 V rated value":"18.5 kW","at 600 V rated value":"32 A","at 690 V rated value":"30 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 y","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":"32 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":"32 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":"9.6 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"27 ... 32 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/a950b22d1184677378f1fb996c7c616b.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=429359&mlfb=3RU2126-4EJ0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4EJ0/alternatives.json"},"ai":{"faq":[{"question":"What is the note 'for message Tripped' on the 3RU2126-4EJ0?","answer":"That note indicates the relay has a built-in trip-indicator flag and a separate auxiliary contact (N/C) that opens when the bimetals trip. It provides a discrete signal — a 'message Tripped' — back to the control system, separate from the contactor coil circuit."},{"question":"What is the depth of the 3RU2126-4EJ0?","answer":"The depth is 85 mm. The overall dimensions are 45 mm wide, 85 mm high, and 85 mm deep — size S0 frame."},{"question":"What compliance documentation does Siemens provide for the 3RU2126-4EJ0?","answer":"The evidence records a Substance Prohibitance date of 10/01/2009, indicating RoHS compliance from that date. The SIRIUS family typically carries CE, UL, CSA, and IEC certifications. For specific documentation (declaration of conformity, UL file number), request it with your RFQ."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4EJ0","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/3RU2126-4EJ0 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}}