{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB2143-4UD0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB2143-4UD0","canonicalUrl":"https://aoctrl.com/siemens/3RB2143-4UD0","factsUrl":"https://aoctrl.com/api/mcp/products/3RB2143-4UD0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RB2143-4UD0 solid-state overload relay, 3-pole, adjustable trip class 5E/10E/20E/30E, screw-type main terminals, spring-loaded auxiliary terminals, 70 mm width, ATEX Ex II (2) GD.","salesMarkdown":"The Siemens 3RB2143-4UD0 is a SIRIUS solid-state overload relay for three-phase motor protection. It mounts directly onto a contactor (fastening method: contactor mounting), saving DIN-rail space in the panel. The trip class is adjustable across CLASS 5E, 10E, 20E, and 30E — meaning you can match the thermal memory to the motor's starting characteristic: fast trip for short-start pumps (5E), slow trip for high-inertia loads like centrifuges (30E). That adjustability is the key differentiator from a fixed-class bimetallic relay. Rated for 3 poles and carries an ATEX Ex II (2) GD protection type, so it is approved for use in potentially explosive atmospheres — the relay can be installed in the safe area and protect motors in Zone 1/21 or Zone 2/22. The relay measures 70 mm wide, 106 mm high, and 124 mm deep. The main circuit accepts stranded wire 2x (10... 50 mm²) or 10... 70 mm², and AWG 2x (10... 1/0) or 1x (10... 2/0). The auxiliary circuit accepts solid 2x (0.25... 1.5 mm²) and AWG 2x (24... 16). Shock resistance is 15g / 11 ms, and surge voltage resistance is 8 kV. EMC immunity includes burst at 2 kV on power ports and 1 kV on signal ports, severity degree 3 per IEC 61000-4-4. Relative humidity during operation can reach 100 %.","metaTitle":"Siemens 3RB2143-4UD0 SIRIUS solid-state overload relay, adju","metaDescription":"Siemens 3RB2143-4UD0 SIRIUS solid-state overload relay, 3-pole, adjustable trip class 5E/10E/20E/30E, ATEX Ex II (2) GD, screw main terminals, spring auxiliary terminals, 70 mm wid","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"Depth":"124 mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"70 mm","Height":"106 mm","Upwards":"0 mm","at 24 V":"2 A","at 60 V":"0.55 A","Forwards":"0 mm","Per Pole":"0.02 W","Stranded":"2x (10 ... 50 mm²), 10 ... 70 mm²","at 110 V":"0.3 A","at 120 V":"4 A","at 125 V":"0.3 A","at 220 V":"0.11 A","at 230 V":"3 A","Backwards":"0 mm","Downwards":"0 mm","Trip Class":"CLASS 5E, 10E, 20E and 30E adjustable","At The Side":"6 mm","During Storage":"-40 ... +80 °C","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","During Transport":"-40 ... +80 °C","Fastening Method":"Contactor mounting","Shock Resistance":"15g / 11 ms","Mounting Position":"any","Product Brand Name":"SIRIUS","Type Of Protection":"PTB 06 ATEX 3001 Ex II (2) GD","Product Designation":"solid-state overload relay","For Main Current Circuit":"screw-type terminals","Substance Prohibitance (Date)":"07/01/2006","at AWG cables for main contacts":"2x (10 ... 1/0), 1x (10 ... 2/0)","For Auxiliary And Control Circuit":"spring-loaded terminals","Relative Humidity During Operation":"100 %","Surge Voltage Resistance Rated Value":"8 kV","at AWG cables for auxiliary contacts":"2x (24 ... 16)","due to burst according to IEC 61000-4-4":"2 kV (power ports), 1 kV (signal ports) corresponds to degree of severity 3","reference code according to IEC 81346-2":"F","Finely Stranded With Core End Processing":"2x (0.25 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","Size Of Contactor Can Be Combined Company-Specific":"S3","electrostatic discharge according to IEC 61000-4-2":"6 kV contact discharge / 8 kV air discharge","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 6 A","insulation voltage with degree of pollution 3 at AC rated value":"1 000 V","Product Component Removable Terminal For Auxiliary And Control Circuit":"Yes","power loss [W] for rated value of the current at AC in hot operating state":"0.05 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"12.5 ... 50 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=494479&mlfb=3RB2143-4UD0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RB2143-4UD0/alternatives.json"},"ai":{"faq":[{"question":"What are the key dimensions of the 3RB2143-4UD0?","answer":"Width is 70 mm, height is 106 mm, and depth is 124 mm. Side clearance required is 6 mm."},{"question":"What wire sizes does the 3RB2143-4UD0 accept?","answer":"Main circuit screw terminals accept stranded 2x (10... 50 mm²) or 10... 70 mm², and AWG 2x (10... 1/0) or 1x (10... 2/0). Auxiliary spring-loaded terminals accept solid 2x (0.25... 1.5 mm²) and AWG 2x (24... 16)."},{"question":"What trip classes are available on the 3RB2143-4UD0?","answer":"Trip class is adjustable to CLASS 5E, 10E, 20E, or 30E, allowing the relay to be tuned to the motor's starting profile."},{"question":"Does the 3RB2143-4UD0 have ATEX approval?","answer":"Yes, it carries protection type PTB 06 ATEX 3001 Ex II (2) GD, suitable for use in potentially explosive atmospheres."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB2143-4UD0","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/3RB2143-4UD0 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}}