{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4BH27-0AV0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4BH27-0AV0","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4BH27-0AV0","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4BH27-0AV0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4BH27-0AV0 direct-on-line starter, S0 size, 20 A AC-3 at 400 V, Class 10 trip, spring-loaded terminals, for 60 mm busbar systems.","salesMarkdown":"## S0 direct starter for 60 mm busbar panels The 3RA2120-4BH27-0AV0 is a SIRIUS direct-on-line starter in size S0, designed for snapping onto 60 mm busbar systems — a common layout in IEC motor control centres where the busbar doubles as the mounting rail and power distribution backbone. The unit ships as a pre-assembled combination: the supplied 3RT2027-2AV00 contactor and 3RA2921-2AA00 link module, wired internally for direct-on-line starting, so the panel builder lands the motor leads and control wires at the spring-loaded terminals without sourcing separate components. ## Mounting envelope and thermal limits Dimensions are 45 mm wide, 260 mm high, and 165 mm deep — the width is the critical panel pitch dimension; at 45 mm it occupies one standard 45 mm module slot on the busbar, leaving adjacent slots free for other S0 feeders or auxiliaries. Clearance requirements: 50 mm above, 20 mm in front, 10 mm below, and 20 mm to each side — these free-air spacings must be maintained inside the enclosure to keep the thermal trip within its calibrated curve at full load. Rated for vertical mounting only; operating ambient range is -20 to +60 °C, with storage and transport limits from -50 to +80 °C.","metaTitle":"Siemens 3RA2120-4BH27-0AV0 SIRIUS Direct Starter, 20 A AC-3","metaDescription":"Siemens 3RA2120-4BH27-0AV0 SIRIUS direct-on-line starter, 20 A at 400 V AC-3, Class 10, S0 size, spring-loaded terminals, 60 mm busbar mount.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"165 mm","Width":"45 mm","title":"3RA2120-4BH27-0AV0","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 13...20 A Spring-type 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":"3 hp","at 400 V rated value":"7 500 kW","at 480 V rated value":"20 A","at 50 Hz rated value":"230 ... 230 V","at 600 V rated value":"20 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":"1.5 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":"15 hp","Of The Supplied Contactor":"3RT2027-2AV00","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":"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)","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":"3RV2021-4BA20","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":"9.8 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","apparent holding power of magnet coil at AC":"9.8 VA","protocol is supported AS-Interface protocol":"No","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":"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,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/6c0a3576d504e3dad0af16960090b795.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=143492&mlfb=3RA2120-4BH27-0AV0"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4BH27-0AV0","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/3RA2120-4BH27-0AV0 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}}