{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2125-4CE27-0FB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2125-4CE27-0FB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2125-4CE27-0FB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2125-4CE27-0FB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2125-4CE27-0FB4 direct-on-line starter, Size S0, 11 kW at 400 V AC-3, Class 10, spring-loaded terminals, screw and snap-on 35 mm DIN rail mounting.","salesMarkdown":"## 11 kW at 400 V — direct-on-line motor starting, SIRIUS Size S0 The 3RA2125-4CE27-0FB4: This covers standard 400 V three-phase motor loads up to 11 kW — pumps, fans, conveyors — in a single pre-assembled unit. It ships with a 3RT2027-2FB40 contactor and a 3RV2021-4CA25 circuit-breaker already linked via the 3RA2921-2AA00 link module. The overload release is thermal bimetallic (Class 10), and the short-circuit trip is magnetic — no separate motor protection relay to wire. Spring-loaded terminals on both the main current circuit and the auxiliary/control circuit speed panel wiring — no screw torque verification needed on the line side. ## Mounting and panel fit — 45 mm wide, screw or DIN rail The starter is 45 mm wide, 243 mm high, and 107 mm deep — it occupies a single S0-size slot on 35 mm standard mounting rail. Fastening method is screw and snap-on; mounting position is vertical. Clearance requirements: 50 mm upwards, 20 mm forwards, 10 mm downwards, 20 mm at the side, 0 mm backwards. Size S0 means the circuit-breaker and contactor share the same frame footprint — the assembly fits into a standard 45 mm-wide DIN cell without overhang. ## Environmental and compliance — -20 to +60 °C operation, 50/60 Hz Rated for operation from -20 to +60 °C ambient, with storage and transport range of -50 to +80 °C. Relative humidity during operation: 10 to 95 %. Surge voltage resistance is 6 kV. Operating frequency is 50... 60 Hz. The starter supports a product extension auxiliary switch (yes). PROFIsafe and PROFINET IO protocols are not integrated — this is a conventional hard-wired direct starter, not a fieldbus slice. ## Sourcing — current lifecycle, quoted to order Sourced through independent distribution channels. No stock-holding claim; quoted per order.","metaTitle":"Siemens 3RA2125-4CE27-0FB4 SIRIUS Direct Starter","metaDescription":"Siemens 3RA2125-4CE27-0FB4 SIRIUS direct-on-line starter, 11 kW at 400 V AC-3, Size S0, Class 10. Spring-loaded terminals. Current lifecycle active.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","title":"3RA2125-4CE27-0FB4","Height":"243 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 16...22 A 24 V DC Spring-type terminal for installation on standard mounting rail (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":"screw and snap-on mounting onto 35 mm standard mounting 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 400 V rated value":"11 000 W","Design Of The Product":"for standard rail or screw mounting","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)","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":"3RV2021-4CA25","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":"22 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":"16 ... 22 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/5038ede257dc3c7e6b9742931acb868f.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=553625&mlfb=3RA2125-4CE27-0FB4"},"ai":{"faq":[{"question":"What is 3RA2125-4CE27-0FB4's depth and width for panel layout?","answer":"Depth is 107 mm, width is 45 mm, height is 243 mm. It mounts vertically on 35 mm DIN rail or with screws, requiring 50 mm clearance above and 20 mm to the side."},{"question":"What compliance documentation does Siemens provide for 3RA2125-4CE27-0FB4?","answer":"The starter carries a NEMA rating of 'other' — it is designed to IEC standards. The degree of protection is not listed as a specific IP code; the NEMA rating is 'other'."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2125-4CE27-0FB4","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/3RA2125-4CE27-0FB4 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}}