{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4AH26-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4AH26-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4AH26-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4AH26-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4AH26-0BB4 direct-on-line starter, S0 size, 16 A AC-3 at 400 V, Class 10 trip, for 60 mm busbar systems, spring-loaded terminals.","salesMarkdown":"## What this SIRIUS direct starter is The Siemens 3RA2120-4AH26-0BB4 is a SIRIUS direct-on-line starter in the S0 size — a pre-assembled combination of a contactor and a circuit-breaker in one unit, ready to snap onto a 60 mm busbar system. It ships with a 3RT2026-2BB40 contactor and a 3RA2921-2AA00 link module already integrated, so you don't have to piece together the motor-starting branch yourself. ## Mounts on 60 mm busbars — panel fit dimensions Designed for snapping onto 60 mm busbar systems, with a vertical mounting position and spring-loaded terminals for the main circuit. The envelope is 45 mm wide, 260 mm tall, and 165 mm deep — that's the S0 footprint, so it fits alongside other S0 feeders on the same busbar. Clearance requirements: 50 mm upward, 20 mm forward, 20 mm at the sides, and 10 mm downward. Zero clearance needed backward — the back of the unit sits flush against the busbar support.","metaTitle":"Siemens 3RA2120-4AH26-0BB4 SIRIUS Direct Starter, 16 A","metaDescription":"Siemens 3RA2120-4AH26-0BB4 SIRIUS direct-on-line starter, 16 A at 400 V AC-3, Class 10, S0 size, for 60 mm busbar systems. Active production, quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"165 mm","Width":"45 mm","Height":"260 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":"for snapping onto 60 mm busbar systems","Mounting Position":"vertical","PROFIsafe protocol":"No","Product Brand Name":"SIRIUS","Type Of Assignment":"2","Product Designation":"Direct (on-line) starter","Size Of Load Feeder":"S0","PROFINET IO protocol":"No","at 230 V rated value":"2 hp","at 400 V rated value":"7 500 kW","at 480 V rated value":"16 A","at 600 V rated value":"16 A","Design Of The Product":"for 60 mm busbars","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-20 ... +60 °C","at 110/120 V rated value":"1 hp","at 200/208 V rated value":"2 hp","at 220/230 V rated value":"5 hp","at 460/480 V rated value":"10 hp","Of The Supplied Contactor":"3RT2026-2BB40","Of The Supplied Link Module":"3RA2921-2AA00","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","at AC-3 at 400 V rated value":"16 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"16 A","Design Of The Overload Release":"thermal (bimetallic)","Of The Supplied Busbar Adapter":"8US1251-5NT11","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":"3RV2021-4AA20","degree of protection NEMA rating":"other","For Auxiliary And Control Circuit":"spring-loaded 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 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":"208 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":"10 ... 16 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/85630f90f9629842cf6ded6b10eb14bc.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=225677&mlfb=3RA2120-4AH26-0BB4","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4AH26-0BB4/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings for the 3RA2120-4AH26-0BB4?","answer":"It is rated 16 A at 400 V AC-3, with a Class 10 trip characteristic. Maximum AC-3 voltage is 690 V. Horsepower ratings include 5 hp at 230 V and 10 hp at 460/480 V."},{"question":"What is the physical size of the 3RA2120-4AH26-0BB4?","answer":"The S0-size unit measures 45 mm wide, 260 mm tall, and 165 mm deep. It snaps onto 60 mm busbar systems with the clearances listed: 50 mm up, 20 mm forward, 20 mm sides, 10 mm down."},{"question":"What contactor and link module come with this starter?","answer":"It ships with a 3RT2026-2BB40 contactor and a 3RA2921-2AA00 link module, pre-assembled as a direct-on-line combination."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4AH26-0BB4","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/3RA2120-4AH26-0BB4 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}}