{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU2126-4DB0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU2126-4DB0","canonicalUrl":"https://aoctrl.com/siemens/3RU2126-4DB0","factsUrl":"https://aoctrl.com/api/mcp/products/3RU2126-4DB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU2126-4DB0 thermal overload relay, Size S0, Trip Class 10, 690 V rated, contactor-mount, screw terminals.","salesMarkdown":"## Active production, direct-mount to SIRIUS contactor The 3RU2126-4DB0 is a current-production SIRIUS thermal overload relay in the S0 frame size. It mounts directly onto the matching SIRIUS contactor — no separate DIN-rail footprint, which saves a slot in the panel and keeps the power wiring between contactor and relay as short as possible. That is the standard class for general-purpose motor starting — it lets the motor accelerate through inrush without nuisance tripping while still protecting against a locked-rotor condition. ## Auxiliary contact ratings and diagnostic signal These are the make/break capacities for the signal circuit — the 690 V rating means it can switch the control voltage directly without an interposing relay in higher-voltage control schemes. Power dissipation is 2.7 W per pole. For a three-phase motor circuit that is 8.1 W total heat into the enclosure — factor this into the panel thermal calculation, especially in a sealed cabinet with multiple relays stacked. ## Environmental range and compliance documentation The compensation ensures the trip curve stays accurate across the ambient range — important for outdoor or unheated enclosure installations where the relay sees the same temperature swings as the motor. RoHS compliance date is 10/01/2009. The relay carries the standard Siemens substance prohibitance documentation for EU markets. MTTF at high demand rate is 2,280 years — a reliability figure relevant for safety circuit assessments where the relay is used in a monitored protective function. ## Sourcing and panel fit The width is the critical dimension for side-by-side mounting on a row of SIRIUS contactors — 45 mm per relay matches the S0 contactor width, so a row of contactor-plus-relay pairs stacks without gaps. Screwdriver requirement is Pozidriv PZ2 with a 5-6 mm shaft diameter — standard electrician's tool, no special bit needed.","metaTitle":"Siemens 3RU2126-4DB0 SIRIUS Overload Relay, Class 10, S0","metaDescription":"Siemens 3RU2126-4DB0 SIRIUS thermal overload relay, Size S0, Trip Class 10, 690 V rated, contactor-mount. Active production. Quoted to order.","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","title":"3RU2126-4DB0","Height":"85 mm","at 24 V":"2 A","at 60 V":"0.3 A","Per Pole":"2.7 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 20...25 A Thermal For motor protection Size S0, Class 10 Contactor mounting 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":"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":"11 kW","at 480 V rated value":"25 A","at 500 V rated value":"15 kW","at 600 V rated value":"25 A","at 690 V rated value":"22 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":"25 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":"25 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":"8.1 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"20 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$27.71","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/d2aed8b8ac288238dfc74fc00788f559.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=22368&mlfb=3RU2126-4DB0"},"ai":{"faq":[{"question":"What is the 'Tripped' note on the 3RU2126-4DB0?","answer":"The note indicates the auxiliary switch output signals a 'Tripped' condition when the relay has operated. It is a diagnostic contact, not a status-for-normal-state contact."},{"question":"What compliance documentation does Siemens provide for 3RU2126-4DB0?","answer":"RoHS compliance is documented with a substance prohibitance date of 10/01/2009. The relay also carries the standard Siemens CE and IEC markings for the SIRIUS product family."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU2126-4DB0","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/3RU2126-4DB0 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}}