{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4DC1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4DC1","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4DC1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4DC1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU2126-4DC1, Class 10, S0 size, 11 kW at 400 V, 690 V rated insulation, spring-loaded terminals.","salesMarkdown":"The Siemens SIRIUS 3RU2126-4DC1 is a thermal overload relay — the thing that sits between your contactor and the motor, watching for a locked rotor or a sustained overcurrent before the windings cook. That's fast enough to protect a standard squirrel-cage induction motor driving a conveyor, a pump, or a kiln fan, but not so fast that it nuisance-trips on a normal start. Rated insulation voltage is 690 V, and it carries motor ratings across common line voltages: 11 kW at 400 V, 15 kW at 500 V, 22 kW at 690 V. At 480 V and 600 V it's rated 25 A. That covers most 400 V class motors up to about 15 kW and 690 V class up to 22 kW. ## Surviving the environment This relay is built for the heat and the grit. That means the bimetallic strip inside still tracks the motor's true thermal state even when the panel is sitting next to a preheater tower or a clinker cooler. Mounts in any position, stand-alone installation. The S0 size — 45 mm wide, 114 mm tall, 95 mm deep — fits a standard DIN rail panel. Spring-loaded terminals accept 2× 0.5 to 2.5 mm² solid or stranded, so you're not fighting screw terminals when the panel is caked with dust. The auxiliary switch is integrated, no add-on block needed. ## Auxiliary contact ratings — what they actually switch The integrated auxiliary contact handles common control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V. At 125 V DC it's 0.22 A, at 220 V DC it's 0.11 A. MTTF under high demand rate is 2,280 years.","metaTitle":"Siemens 3RU2126-4DC1 SIRIUS Thermal Overload Relay, Class 10","metaDescription":"Siemens SIRIUS 3RU2126-4DC1 thermal overload relay, Class 10, 11 kW at 400 V, 690 V rated insulation, -40 to +70 °C operation, spring-loaded terminals. 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":"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","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":"11 kW","at 480 V rated value":"25 A","at 500 V rated value":"15 kW","at 600 V rated value":"25 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":"25 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":"25 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":"8.1 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"20 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/3306dd3d4240f6f68309fd4839852b51.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=516941&mlfb=3RU2126-4DC1","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4DC1/alternatives.json"},"ai":{"faq":[{"question":"What does the 'Note for message Tripped' mean on this relay?","answer":"That note indicates the relay provides a 'Tripped' status signal through its integrated auxiliary switch when the overload release has activated. It's a direct indication that the relay has operated, not just a general alarm."},{"question":"What is the depth of the 3RU2126-4DC1?","answer":"The depth is 95 mm. Overall dimensions are 45 mm wide, 114 mm tall, 95 mm deep — S0 size, fits standard DIN-rail enclosures."},{"question":"Will 3RU2126-4DC1 drop into a panel specified around 3RU2116-1FC1 without rewiring?","answer":"Both are S0 size with the same mounting footprint, so the physical swap is straightforward. However, the 3RU2126-4DC1 has its own current setting range and terminal layout; verify the wiring diagram and the motor FLA before assuming a drop-in replacement. The spring-loaded terminals are the same type."},{"question":"What compliance documentation does this relay carry?","answer":"The evidence lists a substance prohibitance date of 10/01/2009, indicating RoHS compliance. As a Siemens SIRIUS product, it carries CE marking for the European market and is designed to meet IEC/EN 60947-4-1 standards for motor starters. Specific UL/CSA file numbers should be confirmed from the product certificate."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4DC1","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/3RU2126-4DC1 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}}