{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4PB1","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4PB1","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4PB1","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4PB1","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU2126-4PB1 thermal overload relay, CLASS 10, S0 frame size, 95 mm depth, screw-type terminals, auxiliary switch integrated.","salesMarkdown":"## SIRIUS 3RU2126-4PB1 — what this overload relay does The Siemens 3RU2126-4PB1 is a SIRIUS thermal overload relay designed to protect motors against overcurrent and phase-loss conditions. That's the standard for standard-duty motor starting — it lets the motor accelerate under load without nuisance tripping but still clears a locked-rotor condition fast enough to protect the winding insulation. At 400 V rated voltage, this relay handles 18.5 kW motor load; at 500 V it's rated 22 kW, and at 690 V it goes to 30 kW. At 60 V it's only 0.3 A, so watch that if you're running a 60 VDC control bus. Power dissipation per pole is 3.2 W. In a densely packed panel with multiple relays side by side, that adds up — budget the thermal rise in the enclosure, especially if the ambient hits the upper end of the -40 to +70 °C operating range. Temperature compensation is active from -40 to +60 °C, meaning the trip characteristic stays accurate across that band without manual adjustment. Outside that range the thermal model drifts — but the storage and transport limits are wider at -55 to +80 °C. The screw terminal requires a Pozidriv PZ 2 tip with a 5–6 mm shaft diameter — standard electrician's screwdriver, nothing special. No official successor has been published; the 3RU2 series is the active SIRIUS overload relay line and the 3RU2126-4PB1 remains the correct order code for S0-frame CLASS 10 applications at these power ratings.","metaTitle":"Siemens 3RU2126-4PB1 SIRIUS Overload Relay, CLASS 10, S0","metaDescription":"Siemens 3RU2126-4PB1 SIRIUS thermal overload relay, CLASS 10 trip, S0 frame, 95 mm depth. Current production. Quoted to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"Tripped\"","Depth":"95 mm","Width":"45 mm","title":"3RU2126-4PB1","Height":"97 mm","at 24 V":"2 A","at 60 V":"0.3 A","Per Pole":"3.2 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","description":"Overload relay 30...36 A Thermal For motor protection Size S0, Class 10 Stand-alone installation Main circuit: Screw Auxiliary circuit: Screw Manual-Automatic-Reset","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-40 ... +70 °C","During Transport":"-55 ... +80 °C","Fastening Method":"stand-alone installation","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":"18.5 kW","at 480 V rated value":"36 A","at 500 V rated value":"22 kW","at 600 V rated value":"36 A","at 690 V rated value":"30 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":"36 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":"36 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":"9.6 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"30 ... 36 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/1f5776e00e5aac85df19b0420c2d2bfe.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=149667&mlfb=3RU2126-4PB1"},"ai":{"faq":[{"question":"How can I order the 3RU2126-4PB1 and check availability?","answer":"This part is quoted to order against your BOM quantity."},{"question":"What does the 'for message Tripped' note mean on this relay?","answer":"The note indicates that the auxiliary switch integrated into the relay provides a signal output when the overload relay has tripped. This is the 'tripped' message contact that feeds back to the PLC or indicator lamp."},{"question":"What compliance documentation does Siemens provide for the 3RU2126-4PB1?","answer":"The relay carries a substance prohibitance date of 10/01/2009, indicating RoHS compliance. It is designed to meet IEC/EN 60947-4-1 standards for motor protection devices. Full compliance declarations are available from Siemens."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4PB1","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/3RU2126-4PB1 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T19:47:38.189Z","lastPublished":"2026-07-22T19:47:38.189Z","indexable":true}}