{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4DA27-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4DA27-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4DA27-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4DA27-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4DA27-0BB4 direct on-line starter, S0 size, 25 A at 400 V AC-3, Class 10 trip, screw and snap-on 35 mm DIN rail mounting, 45 mm wide.","salesMarkdown":"## 25 A AC-3 direct on-line starter, S0 frame The 3RA2120-4DA27-0BB4: This is a factory-assembled combination starter: it ships with the 3RT2027-1BB40 contactor and the 3RA2921-1BA00 link module already integrated, so the overload relay and contactor are mechanically and electrically coordinated. No separate wiring between the contactor coil and overload trip contacts — the link module handles that internally. ## DIN rail footprint and panel clearances The S0 footprint is 45 mm wide, 193 mm tall, and 107 mm deep — that's the depth from the DIN rail backplane to the front of the enclosure. Clearance requirements: 50 mm above, 20 mm below, 20 mm to the sides, and 20 mm forward for arc-chute venting and wiring access. Zero clearance needed behind the rail. The main circuit terminals are screw-type, sized for standard power wiring up to the 25 A rating. Ambient operating range is -20 to +60 °C with temperature compensation active across that band; storage and transport limits are -50 to +80 °C. Sourced through authorized distribution channels. No stock-holding claim on this listing; each order is quoted individually.","metaTitle":"Siemens 3RA2120-4DA27-0BB4 SIRIUS Motor Starter, 25 A AC-3","metaDescription":"Siemens 3RA2120-4DA27-0BB4 SIRIUS direct on-line starter, 25 A at 400 V AC-3, Class 10 trip, S0 size. Active production, sourced to order against RFQ.","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":"2","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":"11 000 kW","at 480 V rated value":"25 A","at 600 V rated value":"25 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":"2 hp","at 200/208 V rated value":"7.5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"20 hp","Of The Supplied Contactor":"3RT2027-1BB40","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":"25 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"25 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":"3RV2021-4DA10","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":"5.8 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":"325 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":"18 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$156.21","priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/65056089ec2bb97b5e0a82def69647f1.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=458937&mlfb=3RA2120-4DA27-0BB4","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4DA27-0BB4/alternatives.json"},"ai":{"faq":[{"question":"How do I get current pricing and availability for 3RA2120-4DA27-0BB4?","answer":"Submit an RFQ against your BOM quantity."},{"question":"What is the width and depth of this motor starter?","answer":"Width is 45 mm, depth is 107 mm from the DIN rail backplane. Height is 193 mm. Clearances: 50 mm above, 20 mm below, 20 mm sides, 20 mm forward."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4DA27-0BB4","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/3RA2120-4DA27-0BB4 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}}