{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3VA9978-0BB27","brand":"Siemens","brandSlug":"siemens","productSlug":"3VA9978-0BB27","canonicalUrl":"https://aoctrl.com/siemens/3VA9978-0BB27","factsUrl":"https://aoctrl.com/api/mcp/products/3VA9978-0BB27","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 3VA9978-0BB27 undervoltage release, 440-480 V AC 50/60 Hz, 2.5 VA, 3 slots, Overvoltage Category III, pollution degree 3, for 3VA4/5/6 breakers.","salesMarkdown":"The Siemens SENTRON 3VA9978-0BB27 is an undervoltage release accessory for 3VA4, 3VA5, and 3VA6 molded-case circuit breakers. Rated for 440-480 V AC at 50/60 Hz, it draws a maximum apparent power of 2.5 VA. The surge voltage resistance is 4 kV, and it's rated for Overvoltage Category III with a pollution degree of 3 — meaning it's suited for fixed-installation panels in industrial environments where transient overvoltages and conductive dust or moisture are present. Wiring to the auxiliary circuit uses AWG 18 (0.75 mm²) conductors with a stripped length of 10 mm (0.4 in). The connection type is screw-type, standard for panel wiring.","metaTitle":"Siemens 3VA9978-0BB27 SENTRON undervoltage release, 440-480","metaDescription":"Siemens SENTRON 3VA9978-0BB27 undervoltage release for 3VA4/5/6 breakers, 440-480 V AC 50/60 Hz, 2.5 VA, Overvoltage Cat III, pollution degree 3. Active, available to order. Reques","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Circuit Breaker Accessories"],"specifications":{"Depth":"28.8 mm","Width":"25.7 mm","title":"3VA9978-0BB27","Height":"65.1 mm","Accessories":"Auxiliary release","description":"undervoltage release 440-480V AC 50/60Hz accessory for: 3VA4/5/6","Number Of Slots":"3","Stripped Length":"10 mm","lifecycle_stage":"current","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Accessories","Overvoltage Category":"III","Stripped Length [In]":"0.4 in","Design Of The Product":"Auxiliary release","Surge Voltage Resistance":"4 kV","Apparent Power Consumption / Maximum":"2.5 VA","Type Of Electrical Connection / For Auxiliary Circuit":"AWG18 / 750 mm"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/10955ddce331f4c330f1cdcecc9849dc.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=650527&mlfb=3VA9978-0BB27"},"ai":{"faq":[{"question":"What is the 3VA9978-0BB27 used for?","answer":"It's an undervoltage release for Siemens SENTRON 3VA4, 3VA5, and 3VA6 molded-case circuit breakers. It trips the breaker when the supply voltage falls below the rated range, preventing undervoltage damage or unsafe automatic restart."},{"question":"What are the key ratings of 3VA9978-0BB27?","answer":"Rated voltage 440-480 V AC 50/60 Hz, maximum apparent power 2.5 VA, surge voltage resistance 4 kV, Overvoltage Category III, pollution degree 3. Dimensions: 28.8 mm deep, 25.7 mm wide, 65.1 mm high. Three slots required on the breaker."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3VA9978-0BB27","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/3VA9978-0BB27 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}}