{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2125-4EA27-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2125-4EA27-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2125-4EA27-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2125-4EA27-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2125-4EA27-0BB4 non-fused motor starter, direct starter, size S0, 27 A at 600 V, Class 10, 50-60 Hz, 24 V coil, snap-on DIN rail.","salesMarkdown":"## SIRIUS 3RA2 — direct starter, size S0, Class 10 The Siemens 3RA2125-4EA27-0BB4 is a non-fused motor starter from the SIRIUS 3RA2 family, configured as a direct starter in size S0. It ships with a 3RT2027-1BB40 contactor and a 3RA2921-1BA00 link module, so the assembly is matched from the factory — no separate sizing of contactor and overload relay. This is the standard for general-purpose motor starting — compressors, pumps, conveyors — where the start-up transient is brief and a faster trip protects the winding from sustained overload. ## Rated power and current — what the numbers mean for the BOM At 400 V AC-3, the starter is rated 15,000 W (15 kW). At 480 V it delivers 27 A continuous, and at 600 V also 27 A — the current ceiling is the same, but the horsepower equivalent climbs to 25 hp at 575/600 V. The maximum operating voltage is 690 V AC-3, and the unit runs on 50/60 Hz line frequency. The 24 V control coil (rated value) means this starter integrates into a standard 24 VDC control circuit — common in PLC-driven panels where the I/O and safety relays share the same low-voltage bus. No separate 110 V or 230 V control transformer needed for the starter coil. ## Mounting and panel fit — DIN rail or screw-mount The mounting position is vertical. Dimensions: 45 mm wide, 193.1 mm high, 107 mm deep — the S0 footprint is compact enough for a 600 mm wide enclosure with multiple feeders side-by-side. Clearance spaces: 30 mm upwards, 10 mm forwards, 10 mm downwards, 9 mm at the side, 0 mm backwards. The zero-backwards clearance means the starter can be mounted flush against the back panel or a busbar support without additional spacing. ## Wiring and conductor sizing Main contact terminals accept stranded wire from 1 to 10 mm², or two conductors of 2.5 to 6 mm² each. For AWG, that is 2x (16–12) or 2x (14–8). The dual-conductor capability is useful when paralleling a feed-through to a downstream device without a separate terminal block. ## Environmental limits and pollution degree Pollution degree 3 means the starter is rated for industrial environments where conductive dust or occasional condensation may occur — no need for a sealed enclosure in a typical panel.","metaTitle":"Siemens 3RA2125-4EA27-0BB4 SIRIUS Motor Starter","metaDescription":"Siemens 3RA2125-4EA27-0BB4 SIRIUS non-fused motor starter, 27 A at 600 V, Class 10, 50-60 Hz. Active production, quoted to order. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","title":"3RA2125-4EA27-0BB4","Height":"193.1 mm","Upwards":"30 mm","Forwards":"10 mm","Backwards":"0 mm","Downwards":"10 mm","Trip Class":"CLASS 10","At The Side":"9 mm","Rated Value":"24 V","description":"FUSELESS MOTOR STARTER DIRECT START 600V AC SZ S0 27-32A 24V DC SCREW CONNECTION FOR SCREW MOUNTING OR 35 MM RAIL-MOUNTING TYPE OF COORDINATION 2 IQ = 150 KA ALSO FULFILLS TYPE OF COORDINATION 1 1NO+1NC (MSP) 1NO+1NC (CONTACTOR)","During Storage":"-50 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-55 ... +80 °C","Fastening Method":"Snap-mounted to DIN rail or screw-mounted with additional push-in lug","Mounting Position":"vertical","Product Brand Name":"SIRIUS","Type Of Assignment":"2","Degree Of Pollution":"3","Product Designation":"non-fused motor starter 3RA2","Size Of Load Feeder":"S0","at 230 V rated value":"5 hp","at 400 V rated value":"15 000 W","at 480 V rated value":"27 A","at 500 V rated value":"18 500 W","at 600 V rated value":"27 A","Design Of The Product":"direct starter","at 200/208 V rated value":"10 hp","at 220/230 V rated value":"10 hp","at 460/480 V rated value":"20 hp","at 575/600 V rated value":"25 hp","Of The Supplied Contactor":"3RT2027-1BB40","For Main Contacts Stranded":"1 ... 10 mm², 2x (2.5 ... 6 mm²)","Of The Supplied Link Module":"3RA2921-1BA00","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","at AWG cables for main contacts":"2x (16 ... 12), 2x (14 ... 8)","Design Of The Short-Circuit Trip":"magnetic","Of The Supplied Circuit-Breakers":"3RV2021-4EA15","Product Extension Auxiliary Switch":"Yes","holding power of magnet coil at DC":"5.9 W","Surge Voltage Resistance Rated Value":"6 kV","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","number of NC contacts for auxiliary contacts":"2","number of NO contacts for auxiliary contacts":"2","shock resistance according to IEC 60068-2-27":"6g / 11 ms","at 400 V according to IEC 60947-4-1 rated value":"153 000 A","at 500 V according to IEC 60947-4-1 rated value":"100 000 A","operational current at AC-3 at 400 V rated value":"29 A","Type Of Electrical Connection For Main Current Circuit":"screw-type terminals","Mechanical Service Life (Switching Cycles) Of Contactor Typical":"10 000 000","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"416 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":"27 ... 32 A","Connectable Conductor Cross-Section For Main Contacts Finely Stranded With Core End Processing":"1 ... 6 mm²"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/c5b5f4792b04dabfaead2037be1b9c86.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=190579&mlfb=3RA2125-4EA27-0BB4"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2125-4EA27-0BB4","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/3RA2125-4EA27-0BB4 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}}