{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4BA26-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4BA26-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4BA26-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4BA26-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4BA26-0BB4 direct on-line starter, Size S0, 20 A at 400 V AC-3, Class 10, screw-type terminals, 24 V DC coil, screw and snap-on mounting on 35 mm DIN rail.","salesMarkdown":"## What the 20 A AC-3 rating means for the BOM line The 3RA2120-4BA26-0BB4: That 20 A figure governs the full-load current of the motor it can start and stop under load, not the resistive heating current. Maximum operating voltage for AC-3 is 690 V, so the 400 V rating is well inside the device's insulation envelope. The 24 V DC coil is consistent with modern control-voltage architectures in PLC-driven panels. The starter ships as a pre-assembled unit combining a 3RT2026-1BB40 contactor with a 3RA2921-1BA00 link module, reducing wiring and panel space compared to a contactor-plus-overload built from loose components. ## Mounting and thermal clearance for panel layout The S0 form factor — 45 mm wide, 193 mm tall, 107 mm deep — fits standard 200 mm deep enclosures. Clearance requirements are specified: 50 mm above, 20 mm below, 20 mm at the sides, and 20 mm forward. Zero clearance behind the unit, so it can sit flush against the back panel. ## Active production and compliance documentation Substance prohibited date of 10/01/2009 confirms RoHS compliance per the EU directive. The operating temperature range of -20 to +60 °C and storage range of -50 to +80 °C cover most industrial and warehouse environments.","metaTitle":"Siemens 3RA2120-4BA26-0BB4 SIRIUS Direct Starter, 20 A AC-3","metaDescription":"Siemens 3RA2120-4BA26-0BB4 SIRIUS direct starter, 20 A at 400 V AC-3, Class 10, Size S0. Active production, sourced to order. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","Height":"193 mm","Upwards":"50 mm","Forwards":"20 mm","Backwards":"0 mm","Downwards":"10 mm","Trip Class":"CLASS 10","At The Side":"20 mm","Rated Value":"24 ... 24 V","During Storage":"-50 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-50 ... +80 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail","Mounting Position":"vertical","PROFIsafe protocol":"No","Product Brand Name":"SIRIUS","Type Of Assignment":"1","Product Designation":"Direct (on-line) starter","Size Of Load Feeder":"S0","PROFINET IO protocol":"No","at 230 V rated value":"3 hp","at 400 V rated value":"7 500 kW","at 480 V rated value":"20 A","at 600 V rated value":"20 A","Design Of The Product":"for standard rail or screw mounting","For Main Current Circuit":"screw-type terminals","Temperature Compensation":"-20 ... +60 °C","at 110/120 V rated value":"1.5 hp","at 200/208 V rated value":"5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"15 hp","Of The Supplied Contactor":"3RT2026-1BB40","Of The Supplied Link Module":"3RA2921-1BA00","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","at AC-3 at 400 V rated value":"20 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"20 A","Design Of The Overload Release":"thermal (bimetallic)","Design Of The Switching Contact":"electromechanical","Operating Frequency Rated Value":"50 ... 60 Hz","Design Of The Short-Circuit Trip":"magnetic","Of The Supplied Circuit-Breakers":"3RV2021-4BA10","degree of protection NEMA rating":"other","For Auxiliary And Control Circuit":"screw-type terminals","Product Extension Auxiliary Switch":"Yes","Relative Humidity During Operation":"10 ... 95 %","Without Load Current Share Typical":"5.9 W","holding power of magnet coil at DC":"5.9 W","Surge Voltage Resistance Rated Value":"6 kV","at AC in hot operating state per pole":"5.4 W","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","protocol is supported AS-Interface protocol":"No","with high demand rate according to SN 31920":"73 %","reference code according to IEC 81346-2:2019":"Q","shock resistance according to IEC 60068-2-27":"6g / 11 ms","Type Of Voltage Of The Control Supply Voltage":"DC","at 400 V according to IEC 60947-4-1 rated value":"150 000 A","Mechanical Service Life (Operating Cycles) Of Contactor Typical":"10 000 000","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"260 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"13 ... 20 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/ab020d0a2c52fa3f79004d85c4cdc38e.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=333665&mlfb=3RA2120-4BA26-0BB4","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4BA26-0BB4/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RA2120-4BA26-0BB4 and get a price?","answer":"Submit an RFQ for a firm quote."},{"question":"What compliance documentation does Siemens provide for 3RA2120-4BA26-0BB4?","answer":"RoHS compliance is confirmed by the substance prohibited date of 10/01/2009. The operating temperature range is -20 to +60 °C, storage -50 to +80 °C. Full IEC 60947-4-1 certification applies to the SIRIUS product family."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4BA26-0BB4","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/3RA2120-4BA26-0BB4 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}}