{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3VA9978-0BD12","brand":"Siemens","brandSlug":"siemens","productSlug":"3VA9978-0BD12","canonicalUrl":"https://aoctrl.com/siemens/3VA9978-0BD12","factsUrl":"https://aoctrl.com/api/mcp/products/3VA9978-0BD12","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 3VA9978-0BD12 universal auxiliary release, 24V DC, for 3VA4/5/6 molded-case circuit breakers, 3 slots, 28.8 mm depth, 25.7 mm width, 65.1 mm height.","salesMarkdown":"The Siemens 3VA9978-0BD12 is a SENTRON universal auxiliary release designed for the 3VA4, 3VA5, and 3VA6 series of molded-case circuit breakers. It operates on a 24V DC control supply, drawing up to 20 W at maximum DC load. This is the part that trips the breaker remotely — think emergency-stop circuits, undervoltage protection schemes, or PLC-driven shunt-trip commands from a safety relay. Physically, it occupies three slots in the breaker's accessory bay, with a footprint of 25.7 mm wide by 65.1 mm tall by 28.8 mm deep. The auxiliary circuit connection accepts AWG18 wire with a 10 mm (0.4 in) strip length — standard for panel wiring. The surge voltage resistance of 4 kV and the overvoltage category III rating align with IEC 60947-2 requirements for breaker accessories in industrial installations. If your panel is specified around 3VA4/5/6 breakers, this release drops in without modification — no adapter plate, no wiring harness change. A 24 VDC supply feeding this release needs to deliver at least 0.83 A continuously to hold the coil energized; inrush at pickup will be higher. Factor that into your DC load budget — especially if the same supply also feeds PLC outputs or safety relays. Overvoltage category III confirms it's suitable for fixed-installation distribution panels, not just downstream equipment. Together, these two ratings tell the panel builder this release is built for the same environment as the breaker it mounts in.","metaTitle":"Siemens 3VA9978-0BD12 SENTRON Auxiliary Release, 24V DC","metaDescription":"Siemens 3VA9978-0BD12 SENTRON universal auxiliary release, 24V DC, for 3VA4/5/6 breakers. Active lifecycle. Depth 28.8 mm. Quoted to order.","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","Height":"65.1 mm","Accessories":"Auxiliary release","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","consumed active power / at DC / maximum":"20 W","Type Of Electrical Connection / For Auxiliary Circuit":"AWG18 / 750 mm"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=650538&mlfb=3VA9978-0BD12","alternativesUrl":"https://aoctrl.com/api/mcp/products/3VA9978-0BD12/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3VA9978-0BD12?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead time."},{"question":"What is the depth of 3VA9978-0BD12?","answer":"The listed depth is 28.8 mm. Combined with a width of 25.7 mm and height of 65.1 mm, it occupies three accessory slots in a 3VA4/5/6 breaker."},{"question":"Will 3VA9978-0BD12 fit a panel built around 5SY4140-7?","answer":"No — 5SY4140-7 is a miniature circuit breaker (MCB), not a 3VA series molded-case breaker. The 3VA9978-0BD12 is an auxiliary release designed specifically for 3VA4/5/6 breakers; it does not mount in an MCB's accessory bay."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3VA9978-0BD12","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/3VA9978-0BD12 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}