{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU6126-4CB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU6126-4CB0","canonicalUrl":"https://aoctrl.com/siemens/3RU6126-4CB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU6126-4CB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU6126-4CB0, adjustable 17-22 A, Class 10, size S0, 690 V, screw-type terminals for main and auxiliary circuits.","salesMarkdown":"## Motor protection relay for contactor mounting — 17-22 A, Class 10, size S0 The Siemens 3RU6126-4CB0 is a SIRIUS thermal overload relay sized for motor protection in the 17-22 A range, with a Class 10 trip characteristic that clears overloads within 10 seconds at 7.2× Ie — fast enough to protect standard induction motors during stall or jam conditions without nuisance tripping on normal starting curves. Rated for a main circuit voltage of 690 V and a frequency of 50-60 Hz, this three-pole relay mounts directly onto a size S0 contactor (the company-specific S0 frame), saving panel space and eliminating interconnecting wiring between the contactor and overload. Both the main and auxiliary circuits use screw-type terminals; the main terminals accept 2x (0.5-1.5 mm²) solid/stranded or 2x (0.75-2.5 mm²), with a tightening torque of 2-2.5 N·m, while the auxiliary terminals handle 2x (0.5-1.5 mm²) or 2x (0.75-2.5 mm²) as well. The relay's adjustable current response value spans 17-22 A, set via a front dial, and it supports both manual and automatic reset modes — a detail that matters when the motor starter is in a remote or unattended location where automatic restart after a fault is acceptable. ## Panel integration and environmental limits With dimensions of 85 mm depth, 45 mm width, and 85 mm height, the 3RU6126-4CB0 fits the standard S0 contactor footprint and can be mounted in any position. A 6 mm side clearance to grounded parts is required for safe heat dissipation. Relative humidity during operation can reach 90 %, and the relay withstands 8g / 11 ms shock per IEC 60068-2-27 — suitable for installation on vibrating machinery or in mobile equipment. Per-pole dissipation is 2.7 W. These figures drive the thermal budget in a densely packed panel — allow the side clearance and avoid enclosing the relay in a sealed compartment without ventilation. The relay is rated for installation altitudes up to 2 000 m above sea level without derating. Surge voltage resistance is 6 kV, and insulation voltage at pollution degree 3 is 690 V AC. ## Lifecycle and compliance — active production, standard documentation Substance prohibitance compliance date is 05/01/2012, aligning with RoHS and REACH requirements. The relay carries the SIRIUS brand and is designed for motor protection in industrial control panels, typically paired with a size S0 contactor such as the 3RT102 or 3RT103 series. For procurement documentation, the manufacturer provides a CE declaration of conformity, UL/CSA file numbers, and an IEC 60947-4-1 compliance statement. These are available on request at quote time.","metaTitle":"Siemens 3RU6126-4CB0 SIRIUS Thermal Overload Relay, 17-22 A,","metaDescription":"Siemens 3RU6126-4CB0 SIRIUS thermal overload relay, 17-22 A adjustable, Class 10 trip, size S0, 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":"85 mm","Width":"45 mm","Height":"85 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","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 ... 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":"22 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":"17 ... 22 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=621543&mlfb=3RU6126-4CB0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU6126-4CB0/alternatives.json"},"ai":{"faq":[{"question":"How do I get current pricing and availability for 3RU6126-4CB0?","answer":"Submit an RFQ through this listing. Pricing and stock are confirmed at quote time — we source through independent distribution and provide a firm lead time with each quotation."},{"question":"What is 3RU6126-4CB0's listed depth (85 mm) on this component line?","answer":"The depth is 85 mm, with a width of 45 mm and height of 85 mm. This matches the standard S0 contactor footprint for direct mounting."},{"question":"What compliance documentation does this brand provide for 3RU6126-4CB0 (RoHS, REACH, UL, IEC)?","answer":"The relay complies with RoHS/REACH (substance prohibitance date 05/01/2012) and is designed per IEC 60947-4-1. CE, UL, and CSA documentation is available on request."},{"question":"Will 3RU6126-4CB0 drop into a panel that was specified around 3RT1017-1AP04-3MA0 without rewiring?","answer":"The 3RU6126-4CB0 is a size S0 overload relay designed to mount directly onto a size S0 contactor. If the panel was built around a size S0 contactor (e.g., 3RT102 or 3RT103 series), the relay will fit mechanically and electrically without rewiring, provided the current range matches."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU6126-4CB0","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/3RU6126-4CB0 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}}