{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3VA9978-0BB20","brand":"Siemens","brandSlug":"siemens","productSlug":"3VA9978-0BB20","canonicalUrl":"https://aoctrl.com/siemens/3VA9978-0BB20","factsUrl":"https://aoctrl.com/api/mcp/products/3VA9978-0BB20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON auxiliary release, undervoltage release 24 V AC 50/60 Hz, 3 slots, 28.8 mm depth, 25.7 mm width, 65.1 mm height.","salesMarkdown":"The 3VA9978-0BB20: The 28.8 mm depth, 25.7 mm width, and 65.1 mm height match the accessory slot on the 3VA4/5/6 breaker body — it clips into the three-slot auxiliary bay on the side of the breaker. Overvoltage category III and a 4 kV surge voltage resistance mean this release is rated for the transient environment of a main distribution panel, not just a sub-panel. No official successor exists because none is needed.","metaTitle":"Siemens 3VA9978-0BB20 SENTRON undervoltage release, 24 V AC","metaDescription":"Undervoltage release for 3VA4/5/6 breakers, 24 V AC 50/60 Hz, 2 VA max, 4 kV surge. Active production. Quoted on request.","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":"3VA9978-0BB20","Height":"65.1 mm","Accessories":"Auxiliary release","description":"undervoltage release 24V 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 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/8fbca5ce7cf385ae9edd6e42d958dd30.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=650524&mlfb=3VA9978-0BB20"},"ai":{"faq":[{"question":"What is the 3VA9978-0BB20 used for?","answer":"This is an undervoltage release accessory for Siemens SENTRON 3VA4, 3VA5, and 3VA6 molded-case circuit breakers. It trips the breaker when the control voltage (24 V AC) drops below the dropout threshold, providing undervoltage protection for downstream loads."},{"question":"What are the key dimensions of the 3VA9978-0BB20?","answer":"Depth is 28.8 mm, width is 25.7 mm, height is 65.1 mm — sized to fit the three-slot auxiliary bay on the side of the 3VA4/5/6 breaker."},{"question":"Where can I buy the 3VA9978-0BB20 and how is it quoted?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3VA9978-0BB20","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/3VA9978-0BB20 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}}