{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU7126-1KB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU7126-1KB0","canonicalUrl":"https://aoctrl.com/siemens/3RU7126-1KB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU7126-1KB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU7126-1KB0, S0 size, 12.5 A rated operational current, Class 10 trip, screw-type terminals, IP20 front and terminal protection.","salesMarkdown":"The Siemens 3RU7126-1KB0 is a SIRIUS thermal overload relay, size S0, designed to protect three-phase AC motor circuits against overload and phase loss. It mounts directly onto a SIRIUS contactor (S0 frame) via the contactor mounting fastening method, forming a compact motor starter assembly for DIN-rail or panel integration. Rated operational current is 12.5 A at up to 690 V AC/DC, 50/60 Hz. Class 10 trip curve. The relay is rated for a -20 to +55 °C operating ambient, with storage down to -25 °C. Mounts directly onto SIRIUS S0 contactors. Side spacing to grounded parts requires 6 mm minimum. Screw terminals for both main and auxiliary circuits: main terminals torque to 2–2.5 N·m, auxiliary to 0.8–1.2 N·m. Accepts 2× (0.5–1.5 mm²) solid/stranded or 2× (0.75–2.5 mm²) with ferrules. The relay has a surge voltage withstand of 6 kV and insulation voltage of 690 V at pollution degree 3.","metaTitle":"Siemens 3RU7126-1KB0 SIRIUS Thermal Overload Relay, 12.5 A,","metaDescription":"Siemens 3RU7126-1KB0 SIRIUS thermal overload relay, 12.5 A rated current, Class 10 trip, S0 size. Screw terminals, IP20. Active production. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Depth":"96 mm","Width":"45 mm","Height":"97 mm","at 24 V":"3 A","Per Pole":"2.2 W","at 230 V":"2 A","Trip Class":"CLASS 10","On The Front":"IP20","Of The Terminal":"IP20","lifecycle_stage":"current","During Operation":"-20 ... +55 °C","During Transport":"-25 ... +70 °C","Fastening Method":"Contactor mounting","Mounting Position":"with vertical mounting surface +/-135° rotatable, with vertical mounting surface +/- 45° tiltable to the front and back","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Thermal overload relay","Size Of Overload Relay":"S0","For Main Current Circuit":"screw-type terminals","power loss [W] total typical":"6.6 W","Operating Voltage Rated Value":"690 V","Design Of The Overload Release":"thermal","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"12.5 A","For Auxiliary And Control Circuit":"screw-type terminals","Relative Humidity During Operation":"0 ... 90 %","Surge Voltage Resistance Rated Value":"6 kV","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","Type Of Voltage For Main Current Circuit":"AC/DC","For Main Contacts With Screw-Type Terminals":"2 ... 2.5 N·m","shock resistance according to IEC 60068-2-27":"8g / 11 ms","Required Spacing For Grounded Parts At The Side":"6 mm","For Auxiliary Contacts With Screw-Type Terminals":"0.8 ... 1.2 N·m","Size Of Contactor Can Be Combined Company-Specific":"S0","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","operational current of auxiliary contacts at DC-13 at 24 V":"1 A","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","insulation voltage with degree of pollution 3 at AC rated value":"690 V","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":"9 ... 12.5 A","Design Of The Fuse Link For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 6 A, quick: 10 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=1534244&mlfb=3RU7126-1KB0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU7126-1KB0/alternatives.json"},"ai":{"faq":[{"question":"What contactor does the 3RU7126-1KB0 mount onto?","answer":"It mounts directly onto SIRIUS S0-size contactors via the contactor mounting fastening method, forming a one-piece motor starter assembly."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU7126-1KB0","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/3RU7126-1KB0 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}}