{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU6126-4DB1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU6126-4DB1","canonicalUrl":"https://aoctrl.com/siemens/3RU6126-4DB1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU6126-4DB1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU6126-4DB1 thermal overload relay, 20-25 A adjustable, Class 10, size S0, screw terminals, 690 V, 50-60 Hz.","salesMarkdown":"The Siemens SIRIUS 3RU6126-4DB1 is a thermal overload relay for motor protection, adjustable from 20 to 25 A and rated for a 3-pole main circuit at up to 690 V, 50-60 Hz. Sized for the S0 contactor footprint, it mounts standalone or directly onto a SIRIUS S0 contactor, sharing the same DIN-rail or screw-mount pattern. The adjustable current range of 20-25 A sets the motor full-load current (FLC) it protects; you dial in the exact nameplate FLC. Class 10 trip characteristic means the relay clears a fault before the motor winding insulation degrades — critical for pumps, fans, and compressors that see repetitive starts. The S0 size (45 mm wide, 97 mm tall, 95 mm deep) fits standard 45 mm DIN-rail spacing; the 6 mm side clearance to grounded parts is a minimum for air circulation and arc flash mitigation, not a suggestion. Screw terminals on both main and auxiliary circuits accept 2x (0.5-1.5 mm²) solid/stranded or 2x (0.75-2.5 mm²) with ferrules, so it plays nice with existing panel wiring without adapters. Surge voltage rating 6 kV. Substance prohibitance per RoHS and REACH is declared as of May 1, 2012, meaning it meets EU substance restrictions for ongoing compliance documentation. Mounts in any position — horizontal, vertical, or flat — no derating required for orientation. Standalone installation means it doesn't need a contactor underneath; you can bolt it directly to the panel backplate or DIN rail. When combined with an S0 contactor, the relay clips onto the contactor's frame, sharing the power connections through the contactor's through-hole terminals — that saves wiring time and reduces point-to-point failure risk. Tightening torque for main screw terminals is 2-2.5 N·m; auxiliary terminals follow the same spec. Use a torque screwdriver; overtightening strips the brass threads. That's low enough for a sealed enclosure without active cooling, but if you're packing multiple relays in a small box, sum the heat and check the enclosure's thermal rise.","metaTitle":"Siemens 3RU6126-4DB1 SIRIUS Overload Relay, 20-25 A, Class 1","metaDescription":"Siemens SIRIUS 3RU6126-4DB1 thermal overload relay, 20-25 A adjustable, Class 10 trip, S0 size, 690 V, screw terminals. Active production, sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Depth":"95 mm","Width":"45 mm","title":"3RU6126-4DB1","Height":"97 mm","at 24 V":"2 A","Per Pole":"2.7 W","at 110 V":"0.22 A","at 230 V":"2 A","Trip Class":"CLASS 10","description":"Overload relay 20...25 A size S0, class 10, for motor protection stand-alone installation main circuit: screw terminal AUX. circuit: screw terminal manual automatic reset","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 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Thermal overload relay","For Main Current Circuit":"screw-type terminals","power loss [W] total typical":"6.2 W","Operating Voltage Rated Value":"690 V","Substance Prohibitance (Date)":"05/01/2012","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":"2x (16 ... 12), 2x (14 ... 8)","For Auxiliary And Control Circuit":"screw-type terminals","Relative Humidity During Operation":"0 ... 90 %","Surge Voltage Resistance Rated Value":"6 kV","at AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","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","shock resistance according to IEC 60068-2-27":"8g / 11 ms","Required Spacing For Grounded Parts At The Side":"6 mm","Size Of Contactor Can Be Combined Company-Specific":"S0","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","Tightening Torque For Main Contacts With Screw-Type Terminals":"2 ... 2.5 N·m","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":"8.1 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"20 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/dcb9f60df34b785d7a975644a062ab48.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=621546&mlfb=3RU6126-4DB1"},"ai":{"faq":[{"question":"What are the key dimensions?","answer":"Width 45 mm, height 97 mm, depth 95 mm. Fits standard 45 mm DIN-rail spacing. Requires 6 mm side clearance to grounded parts."},{"question":"Will it drop into a panel specified for a 3RT6023-1BW40 contactor?","answer":"The 3RU6126-4DB1 is designed to mount directly onto SIRIUS S0 contactors like the 3RT1023 or 3RT1044 series. The 3RT6023-1BW40 is a different frame size (S2/S3). It will not physically clip onto that contactor without an adapter. For a panel built around a 3RT6023, you would need the corresponding S2/S3 overload relay (e.g., 3RU6126-4DB1's size S0 is too small). Check the contactor frame size before ordering."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU6126-4DB1","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/3RU6126-4DB1 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}