{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4BH26-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4BH26-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4BH26-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4BH26-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4BH26-0BB4 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":"The 3RA2120-4BH26-0BB4 is a Siemens SIRIUS direct-on-line starter in size S0, combining a contactor and overload relay into a single assembly for snapping onto 60 mm busbar systems. ## Mounting and termination — busbar snap-on with spring terminals Designed specifically for 60 mm busbar systems, the starter snaps onto the busbar without tools — no DIN rail required, though the vertical mounting position is mandatory. Main circuit connections use spring-loaded terminals (cage clamp style), which reduces wiring time compared to screw terminals and holds solid or ferruled stranded wire without retorquing. Dimensions are 45 mm wide × 260 mm high × 165 mm deep; clearance requirements are 50 mm upward, 20 mm forward, 10 mm downward, and 20 mm at the side — plan the busbar layout accordingly. ## What comes in the box — supplied contactor and link module The starter ships with the contactor 3RT2026-2BB40 and the link module 3RA2921-2AA00 pre-assembled — no separate ordering of the contactor and overload for this combination. The supplied contactor is matched to the S0 frame size and the 20 A AC-3 rating, so the coordination between the contactor and overload is factory-set for Type 1 or Type 2 coordination depending on the upstream breaker selection. ## Environmental and compliance — operating range and RoHS Rated for operation from -20 °C to +60 °C with temperature compensation active across the same range; storage and transport limits extend from -50 °C to +80 °C. RoHS compliance date is 10/01/2009 — the starter meets the EU RoHS directive for substances of concern as of that date.","metaTitle":"Siemens 3RA2120-4BH26-0BB4 SIRIUS Direct Starter, 20 A AC-3","metaDescription":"Siemens SIRIUS 3RA2120-4BH26-0BB4 direct-on-line starter, 20 A at 400 V AC-3, Class 10, S0 size, spring terminals. 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":"3RA2120-4BH26-0BB4","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 13...20 A 24 V DC Spring-type terminal for 60 mm busbar systems Type of coordination 1, 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":"1","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 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":"5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"15 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":"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":"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":"5.4 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":"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/34d5818d718421d4a31805852f7d01d1.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=331374&mlfb=3RA2120-4BH26-0BB4"},"ai":{"faq":[{"question":"What is the 3RA2120-4BH26-0BB4 rated for in motor duty?","answer":"The Class 10 trip characteristic protects standard induction motors during start-up."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4BH26-0BB4","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/3RA2120-4BH26-0BB4 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}}