{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4FC1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4FC1","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4FC1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4FC1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU2126-4FC1, S0 size, Class 10, spring-loaded terminals, 690 V rated, 50...60 Hz.","salesMarkdown":"It protects motors against overcurrent by monitoring the phase current and tripping a built-in auxiliary contact when the thermal model reaches the threshold. It is temperature-compensated from -40 to +60 °C, so the trip curve stays accurate across the panel's ambient range. The auxiliary switch is integrated — no add-on module needed for the tripped signal. The note \"for message \\\"Tripped\\\"\" on the spec line refers to the auxiliary contact state that signals an overload condition back to the PLC or annunciator. That contact is what the controls integrator wires to the digital input for the motor-fault summary. The S0 footprint is 45 mm wide × 114 mm high × 95 mm deep, so it fits a standard 45 mm slot in a motor-starter row. Spring-loaded terminals on the main circuit accept 2× (0.5...2.5 mm²) solid or stranded copper — no screw torque to verify, just strip and push. The auxiliary contact ratings cover most control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V. At 60 V it's 0.3 A; at 110 V and 125 V it's 0.22 A; at 220 V it's 0.11 A. Power dissipation per pole is 3.2 W — factor that into the enclosure thermal budget if you're packing several relays side by side. The substance prohibitance date of 10/01/2009 aligns with the original EU RoHS compliance deadline. The relay is compliant with RoHS and REACH as a standard SIRIUS product. No special documentation beyond the standard declaration is required for most industrial panels.","metaTitle":"Siemens 3RU2126-4FC1 SIRIUS Thermal Overload Relay, Class 10","metaDescription":"Siemens 3RU2126-4FC1 SIRIUS thermal overload relay, Class 10, S0 size. 690V rated, spring-loaded terminals. Active production. Available to order. Request quote for price and stock","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":"18.5 kW","at 480 V rated value":"40 A","at 500 V rated value":"22 kW","at 600 V rated value":"40 A","at 690 V rated value":"37 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":"40 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":"40 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":"34 ... 40 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/ea3801e8f43a5e71bd75f0a61904880a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=342630&mlfb=3RU2126-4FC1","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4FC1/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RU2126-4FC1 and how do I get a price?","answer":"We source this part through independent distribution and quote it to order against an RFQ. Submit a request for current availability and pricing — no commitment needed to get a number."},{"question":"What is the note \"for message Tripped\" on the 3RU2126-4FC1 spec line?","answer":"It refers to the auxiliary contact that changes state when the relay trips on overload — that contact is wired to a PLC input or annunciator to signal the motor fault."},{"question":"What compliance documentation does Siemens provide for 3RU2126-4FC1?","answer":"As a standard SIRIUS product it is RoHS and REACH compliant, with a substance prohibitance date of 10/01/2009. Standard declarations are available through the Siemens support portal."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4FC1","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/3RU2126-4FC1 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}}