{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4ND27-0FB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4ND27-0FB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4ND27-0FB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4ND27-0FB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4ND27-0FB4 direct online starter, S0 frame, 15 kW at 400 V AC-3, Class 10, 45 mm wide, for 60 mm busbar systems.","salesMarkdown":"## Active production — what ships in the carton The 3RA2120-4ND27-0FB4: The kit ships complete: the supplied contactor is 3RT2027-1FB40, the link module is 3RA2921-1BA00, the busbar adapter is 8US1251-5NT10, and the circuit-breaker is 3RV2021-4NA10. No holes in the box — every piece needed for a 60 mm busbar install is included. ## Motor load sizing and trip coordination Rated 15 kW at 400 V, 50-60 Hz, AC-3 duty with a maximum switching voltage of 690 V. Overload protection is thermal bimetallic; short-circuit protection is magnetic via the supplied 3RV2021-4NA10 circuit-breaker. The trip class and breaker size are coordinated for the S0 frame — no separate sizing exercise needed for the motor branch. ## Busbar mount — space claim and clearances Snaps directly onto 60 mm busbar systems — no DIN rail adapter required. The mounting position is vertical only. Dimensions: 45 mm wide, 260 mm tall, 165 mm deep. Clearance requirements: 50 mm upwards, 20 mm forwards, 10 mm downwards, 20 mm at the side, 0 mm backwards. The backwards clearance of zero means the unit sits flush against the busbar backplane — plan the busbar depth accordingly. ## Termination and environmental limits Screw-type terminals on both the main current circuit and the auxiliary/control circuit. The auxiliary switch extension is supported (product extension auxiliary switch: Yes), so adding a second NC/NO block is straightforward. Operates from -20 to +60 °C with temperature compensation active across that range. Storage and transport range is -50 to +80 °C. Relative humidity during operation: 10 to 95 %.","metaTitle":"Siemens 3RA2120-4ND27-0FB4 SIRIUS Motor Starter","metaDescription":"Siemens 3RA2120-4ND27-0FB4 SIRIUS direct online starter, S0 frame, 15 kW at 400 V AC-3, Class 10, snaps onto 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":"165 mm","Width":"45 mm","title":"3RA2120-4ND27-0FB4","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","description":"Load feeder fuseless, Direct-on-line starting 400 V AC, Size S0 23.0...28.0 A 24 V DC 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) with diode combination plugged in at the front","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 400 V rated value":"15 000 W","Design Of The Product":"for 60 mm busbars","For Main Current Circuit":"screw-type terminals","Temperature Compensation":"-20 ... +60 °C","Of The Supplied Contactor":"3RT2027-1FB40","Of The Supplied Link Module":"3RA2921-1BA00","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","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":"3RV2021-4NA10","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 %","Surge Voltage Resistance Rated Value":"6 kV","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","protocol is supported AS-Interface protocol":"No","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","operational current at AC-3 at 400 V rated value":"28 A","Mechanical Service Life (Switching Cycles) Of Contactor Typical":"10 000 000","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"23 ... 28 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/c8e60d815e4d2bc7d2f75f65b19f54c7.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=207020&mlfb=3RA2120-4ND27-0FB4"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4ND27-0FB4","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/3RA2120-4ND27-0FB4 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}}