{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2125-4BH27-0FB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2125-4BH27-0FB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2125-4BH27-0FB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2125-4BH27-0FB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2125-4BH27-0FB4 direct-on-line starter, S0 size, 7.5 kW at 400 V AC-3, Class 10, spring-loaded terminals, for 60 mm busbar systems.","salesMarkdown":"## Motor rating and protection class for the BOM line The 3RA2125-4BH27-0FB4: The thermal overload release is bimetallic (Class 10), and the short-circuit trip is magnetic, giving coordinated motor protection within the S0 feeder size. The supplied contactor is 3RT2027-2FB40, and the supplied circuit-breaker is 3RV2021-4BA25 — these are the matched components that deliver the listed rating. For audit purposes, the combination is factory-tested for coordination under IEC 60947-4-1. ## Mounting and wiring for panel integration Designed for snapping onto 60 mm busbar systems, with a vertical mounting position. The enclosure dimensions are 45 mm wide, 260 mm high, and 165 mm deep — the 45 mm width fits standard S0 feeder slots in a distribution board. Both main and auxiliary/control circuits use spring-loaded terminals, which reduces wiring time and ensures consistent contact pressure without retorquing. Clearance distances: 50 mm upwards, 20 mm forwards, 10 mm downwards, 20 mm at the side — factor these into the gland plate and cable routing. The operating temperature range is -20 to +60 °C, with temperature compensation active across that band, so it is suitable for unconditioned enclosures in most industrial environments.","metaTitle":"Siemens 3RA2125-4BH27-0FB4 SIRIUS Direct Starter","metaDescription":"Siemens 3RA2125-4BH27-0FB4 SIRIUS direct-on-line starter, 7.5 kW 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":"3RA2125-4BH27-0FB4","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 13...20 A 24 V DC 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) 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":"7 500 W","Design Of The Product":"for 60 mm busbars","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-20 ... +60 °C","Of The Supplied Contactor":"3RT2027-2FB40","Of The Supplied Link Module":"3RA2921-2AA00","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":"8US1251-5NT11","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":"3RV2021-4BA25","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 %","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","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","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":"15.5 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":"13 ... 20 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/da58eaecce10f19a69c7168ce023996a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=552137&mlfb=3RA2125-4BH27-0FB4"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2125-4BH27-0FB4","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/3RA2125-4BH27-0FB4 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}