{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-1HB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-1HB0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-1HB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-1HB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU2126-1HB0, CLASS 10 trip class, S0 frame size, 690 V rated, screw terminals, contactor mounting.","salesMarkdown":"The Siemens SIRIUS 3RU2126-1HB0 is a thermal overload relay — the part that sits between a contactor and a motor, watching the current draw and tripping if the motor starts pulling too hard for too long. That's fast enough to protect the motor windings but slow enough to let starting inrush pass without nuisance trips. It's rated for a maximum of 690 V, and the switching currents vary by voltage: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, and 0.75 A at 690 V. For motor protection, it's sized to handle 3 kW at 400 V, 4 kW at 500 V, and 5.5 kW at 690 V. The AC-3e rated maximum is 690 V, so it's built for three-phase motor duty. ## How it mounts and wires in This relay is S0 frame size — that's the smallest of the SIRIUS overload relay frames, measuring 85 mm tall, 45 mm wide, and 85 mm deep. It fastens directly to the contactor via the contactor mounting method, so it snaps onto the bottom of a matching SIRIUS contactor without extra hardware. The main current circuit uses screw-type terminals, and the screwdriver tip needed is Pozidriv PZ 2 with a shaft diameter of 5 to 6 mm. Wire range is 2x (0.5 to 1.5 mm²) solid or stranded, or 2x (0.75 to 2.5 mm²). The auxiliary switch is integrated right into the body, so there's no separate add-on to buy for the trip-indication signal. Mounting position is any, which helps in tight panels where you're cramming gear together. Temperature compensation is active from -40 to +60 °C, meaning the trip curve stays accurate even if the panel's sitting next to a hot motor or a steam line. That's a wide thermal envelope — it'll survive a summer in a non-climate-controlled enclosure or a winter on a loading dock. The note reads for message Tripped — the auxiliary switch signals the PLC or indicator when the relay has tripped. Substance prohibitance date is 10/01/2009.","metaTitle":"Siemens 3RU2126-1HB0 SIRIUS thermal overload relay, CLASS 10","metaDescription":"Siemens SIRIUS 3RU2126-1HB0 thermal overload relay, CLASS 10 trip, S0 frame, 690 V rated, 85x45x85 mm. Current production. RFQ for pricing.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"Tripped\"","Depth":"85 mm","Width":"45 mm","Height":"85 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","at 690 V":"0.75 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","For Main Contacts":"M4","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","at 400 V rated value":"3 kW","at 480 V rated value":"8 A","at 500 V rated value":"4 kW","at 600 V rated value":"8 A","at 690 V rated value":"5.5 kW","Size Of Overload Relay":"S0","For Main Current Circuit":"screw-type terminals","Temperature Compensation":"-40 ... +60 °C","MTTF with high demand rate":"2 280 a","Design Of Screwdriver Shaft":"Diameter 5 ... 6 mm","Size Of The Screwdriver Tip":"Pozidriv PZ 2","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":"8 A","at AWG cables for main contacts":"2x (16 ... 12), 2x (14 ... 8)","For Auxiliary And Control Circuit":"screw-type 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 ... 16), 2x (18 ... 14)","Of The Auxiliary And Control Contacts":"M3","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","For Main Contacts With Screw-Type Terminals":"2 ... 2.5 N·m","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","For Auxiliary Contacts With Screw-Type Terminals":"0.8 ... 1.2 N·m","operational current at AC-3e at 400 V rated value":"8 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":"5.5 ... 8 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$30.48","priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/b1661c855ce8dd70de67af499835d0ee.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=159923&mlfb=3RU2126-1HB0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-1HB0/alternatives.json"},"ai":{"faq":[{"question":"What does the note for message Tripped mean?","answer":"The note indicates that the auxiliary switch integrated into the relay provides a signal when the relay has tripped due to overload. That signal can be wired to a PLC input or indicator lamp to show the motor is in a tripped state."},{"question":"What is the trip class of this relay?","answer":"It has a CLASS 10 trip class, meaning it will trip within 10 seconds under locked-rotor conditions, suitable for standard induction motor starting."},{"question":"Will the 3RU2126-1HB0 fit a panel designed for the 3RT1023-1AL20 contactor?","answer":"The 3RU2126-1HB0 uses contactor mounting and is the S0 frame size, which is the matching overload relay for SIRIUS S0 contactors like the 3RT1023 series. It should mount directly to the contactor without rewiring the main power circuit, but verify the specific contactor model's compatibility for the auxiliary wiring."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-1HB0","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/3RU2126-1HB0 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}}