{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4PJ0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4PJ0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4PJ0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4PJ0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS thermal overload relay, 3RU2126-4PJ0, Class 10, Size S0, 690 V rated, 18.5 kW at 400 V, contactor mounting.","salesMarkdown":"Rated at 690 V and sized for the S0 frame, this relay mounts directly onto a contactor of the same frame, keeping the panel wiring compact. The thermal release is temperature-compensated from -40 to +60 °C, so the trip point stays consistent whether the panel sits in a cold warehouse or a warm machine room. The headline power rating is 18.5 kW at 400 V, which tells you the motor it can protect in a standard 400 V three-phase system — match this to your motor nameplate, not the contactor rating. At 480 V it carries 36 A; at 600 V the same 36 A, and at 690 V it handles 30 kW — the current limit is the same across the higher voltages, so the relay's thermal element is current-limited, not voltage-limited, above 480 V. The auxiliary switch is integrated — one normally-open and one normally-closed contact, rated at 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. That covers the feedback signal to the PLC or the trip indication lamp without an add-on block. The note \"for message 'Tripped'\" on the product line means the auxiliary contacts change state when the bimetals have reached the trip threshold — this is the signal you wire back to the control system to flag an overload condition. Fastens directly onto the contactor — no DIN rail needed, which saves a slot in the panel. Mounting position is any orientation, so it fits in tight enclosures or vertical bus stacks. Main circuit connection is via ring cable lugs, M4 screws. The auxiliary wiring uses screw terminals; the screwdriver shaft should be 5 to 6 mm diameter with a Pozidriv PZ2 tip. MTTF at high demand rate is 2,280 years. Because it is active and standard, lead time is typically the factory lead for the SIRIUS line — no broker or surplus premium involved.","metaTitle":"Siemens 3RU2126-4PJ0 SIRIUS thermal overload relay, Class 10","metaDescription":"Siemens 3RU2126-4PJ0 SIRIUS thermal overload relay, Class 10 trip, S0 size, 690 V rated, 18.5 kW at 400 V. Current production. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"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":"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","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","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":"Ring cable lug connection","Temperature Compensation":"-40 ... +60 °C","MTTF with high demand rate":"2 280 y","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","For Auxiliary And Control Circuit":"ring terminal lug connection","Between Main And Auxiliary Circuit":"440 V","Relative Humidity During Operation":"10 ... 95 %","Display Version For Switching Status":"Slide switch","For Main Contacts For Ring Cable Lug":"2.5 ... 2 N·m","Surge Voltage Resistance Rated Value":"6 kV","Of The Auxiliary And Control Contacts":"M3","Between Auxiliary And Auxiliary Circuit":"440 V","reference code according to IEC 81346-2":"F","Number Of Poles For Main Current Circuit":"3","For Auxiliary Contacts For Ring Cable Lug":"0.8 ... 1.2 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","operational current at AC-3e at 400 V rated value":"36 A","Size Of Contactor Can Be Combined Company-Specific":"S0","Outer Diameter Of The Usable Ring Cable Lug Maximum":"7.5 mm","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,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=106148&mlfb=3RU2126-4PJ0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4PJ0/alternatives.json"},"ai":{"faq":[{"question":"What does the note 'for message Tripped' mean?","answer":"It means the integrated auxiliary switch changes state when the bimetals reach the trip temperature, providing a signal to the control system that the relay has tripped on overload."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4PJ0","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/3RU2126-4PJ0 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}}