{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4ED27-0AP0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4ED27-0AP0","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4ED27-0AP0","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4ED27-0AP0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4ED27-0AP0 direct online starter, S0 size, 29 A AC-3 at 400 V, Class 10, 60 mm busbar mount, screw terminals.","salesMarkdown":"## SIRIUS direct starter for 60 mm busbar systems The Siemens 3RA2120-4ED27-0AP0 is a SIRIUS direct online starter, size S0, designed for snapping onto 60 mm busbar systems — a common panel layout in IEC switchgear and motor control centres. The Class 10 trip characteristic means it will disconnect before the motor windings overheat under a locked-rotor condition — critical for standard induction motor starts. ## Dimensions and clearance for panel fit The unit measures 155 mm deep, 45 mm wide, and 260 mm tall. The narrow 45 mm width fits two units side-by-side in a standard 100 mm wide busbar chamber. Clearance requirements around the starter: 50 mm upwards, 20 mm forwards, 10 mm downwards, and 20 mm at the side. Zero clearance needed backwards — it sits flush against the busbar. These gaps allow for cooling airflow and tool access during wiring. ## Supplied components and termination This starter ships with a 3RT2027-1AP00 contactor and a 3RA2921-1AA00 link module pre-assembled. Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Mounting position is vertical only.","metaTitle":"Siemens 3RA2120-4ED27-0AP0 SIRIUS Direct Starter, 29 A AC-3","metaDescription":"Siemens SIRIUS 3RA2120-4ED27-0AP0 direct online starter, 29 A at 400 V AC-3, Class 10 trip, S0 size for 60 mm busbars. Active production, quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"155 mm","Width":"45 mm","title":"3RA2120-4ED27-0AP0","Height":"260 mm","Upwards":"50 mm","Forwards":"20 mm","at 50 Hz":"0.25","Backwards":"0 mm","Downwards":"10 mm","Trip Class":"CLASS 10","At The Side":"20 mm","Rated Value":"690 V","description":"Load feeder fuseless, Direct-on-line starting 400 V AC, Size S0 27.0...32.0 A 230 V AC screw terminal for 60 mm busbar systems (also fulfills type of coordination 1) Type of coordination 2, Iq = 150 kA 1 NO+1 NC (contactor)","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":"5 hp","at 400 V rated value":"15 000 kW","at 480 V rated value":"27 A","at 50 Hz rated value":"230 ... 230 V","at 600 V rated value":"27 A","Design Of The Product":"for 60 mm busbars","For Main Current Circuit":"screw-type terminals","Temperature Compensation":"-20 ... +60 °C","at 110/120 V rated value":"2 hp","at 200/208 V rated value":"10 hp","at 220/230 V rated value":"10 hp","at 460/480 V rated value":"20 hp","Of The Supplied Contactor":"3RT2027-1AP00","Of The Supplied Link Module":"3RA2921-1AA00","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","at AC-3 at 400 V rated value":"29 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"29 A","Design Of The Overload Release":"thermal (bimetallic)","Of The Supplied Busbar Adapter":"8US1251-5NT10","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":"3RV2021-4EA10","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":"9.8 W","Surge Voltage Resistance Rated Value":"6 kV","at AC in hot operating state per pole":"6.7 W","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","apparent holding power of magnet coil at AC":"9.8 VA","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":"AC","at 400 V according to IEC 60947-4-1 rated value":"150 000 A","Inductive Power Factor With The Holding Power Of The Coil":"0.25","Mechanical Service Life (Operating Cycles) Of Contactor Typical":"10 000 000","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"400 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":"27 ... 32 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/475a7cc50982f2a4dbf3625c0ba0aa95.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=323265&mlfb=3RA2120-4ED27-0AP0"},"ai":{"faq":[{"question":"What is the AC-3 rating of 3RA2120-4ED27-0AP0 at 400 V?","answer":"The trip class is Class 10."},{"question":"What clearance is needed around 3RA2120-4ED27-0AP0 when mounted on busbars?","answer":"Required clearances: 50 mm upwards, 20 mm forwards, 10 mm downwards, and 20 mm at the side. Backwards clearance is 0 mm as it snaps directly onto the 60 mm busbar system."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4ED27-0AP0","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/3RA2120-4ED27-0AP0 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T19:47:38.189Z","lastPublished":"2026-07-22T19:47:38.189Z","indexable":true}}