{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-1FC0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-1FC0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-1FC0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-1FC0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU2126-1FC0 thermal overload relay, Size S0, Trip Class 10, rated 690 V, spring-loaded terminals, contactor mounting.","salesMarkdown":"The Siemens 3RU2126-1FC0 is a SIRIUS thermal overload relay in Size S0, Trip Class 10, with spring-loaded terminals and contactor mounting. At 400 V the relay is rated for 1.5 kW motor load; at 500 V for 2.2 kW; at 690 V for 4 kW. The AC-3e rated maximum voltage of 690 V means the auxiliary contacts can switch motor loads at that voltage level. The operating frequency is 50 to 60 Hz, so it works on either standard line frequency without derating. The auxiliary contact ratings span the control voltages you'll find in a typical panel: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. The 0.3 A at 60 V and 0.22 A at 110 V and 125 V cover the less common control voltages. The per-pole power dissipation is 2.2 W, which matters when you're stacking multiple relays in a confined enclosure — the cumulative heat needs to stay within the cabinet's thermal budget. The relay includes an integrated auxiliary switch (the N/C contact that signals the trip condition) and a thermal overload release mechanism. The note \"for message 'Tripped'\" on the listing refers to the auxiliary contact that changes state when the relay trips, providing a signal to the PLC or indicator lamp. It mounts directly onto a Siemens contactor of matching frame size — the fastening method is contactor mounting, so no DIN rail is required for the relay itself; it clips onto the contactor and the whole assembly snaps onto the DIN rail. The dimensions are 45 mm wide, 102 mm high, and 84 mm deep, which fits the standard S0 footprint. The spring-loaded terminals accept 2× (0.5 to 2.5 mm²) solid or stranded wire, and the screwdriver requirement is a 3 mm shaft diameter with a 3.0 × 0.5 mm tip. ## Environmental range and compliance The relay operates from -40 to +70 °C, with temperature compensation from -40 to +60 °C. MTTF under high-demand rate is 2,280 years.","metaTitle":"Siemens 3RU2126-1FC0 SIRIUS Thermal Overload Relay, Size S0,","metaDescription":"Siemens 3RU2126-1FC0 SIRIUS thermal overload relay, Size S0, Trip Class 10, 690 V rated, spring-loaded terminals, contactor mounting. 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":"84 mm","Width":"45 mm","Height":"102 mm","at 24 V":"2 A","at 60 V":"0.3 A","Per Pole":"2.2 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":"Contactor mounting","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":"1.5 kW","at 480 V rated value":"5 A","at 500 V rated value":"2.2 kW","at 600 V rated value":"5 A","at 690 V rated value":"4 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":"5 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":"5 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":"6.6 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"3.5 ... 5 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/7d07219a439853a6381116536ab19840.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=322216&mlfb=3RU2126-1FC0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-1FC0/alternatives.json"},"ai":{"faq":[{"question":"What is the note 'for message Tripped' on this component line?","answer":"The note refers to the integrated auxiliary switch that changes state when the thermal overload relay trips. That auxiliary contact provides a signal (the 'tripped' message) to a PLC, indicator, or control circuit."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-1FC0","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/3RU2126-1FC0 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}}