{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3VA9908-0BB21","brand":"Siemens","brandSlug":"siemens","productSlug":"3VA9908-0BB21","canonicalUrl":"https://aoctrl.com/siemens/3VA9908-0BB21","factsUrl":"https://aoctrl.com/api/mcp/products/3VA9908-0BB21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 3VA9908-0BB21, undervoltage release accessory for 3VA1 and 3VA20 up to 3VA25 breakers, 48 V AC 50/60 Hz, 2 VA, 4 kV surge, pollution degree 3, 28.8 × 25.7 × 65.1 mm.","salesMarkdown":"It's designed exclusively for the 3VA1 and 3VA20 through 3VA25 molded-case breaker frames. When the control voltage falls, the release opens the breaker mechanism — standard practice for motor feeders, conveyor lines, or crusher drives where an undervoltage condition should isolate the load rather than let it re-accelerate unpredictably. It's a compact unit: 28.8 mm deep, 25.7 mm wide, 65.1 mm tall, with three slots for wiring and a 10 mm strip length on the terminals. ## Ratings that matter for the panel Surge voltage resistance is 4 kV, which aligns with overvoltage category III in a 230/400 V distribution panel. That means it withstands switching transients and indirect lightning-induced spikes without failing — a real concern in mining or mill environments where long cable runs and frequent motor switching are the norm. The stripped length spec of 10 mm (0.4 in) is standard for spring-cage or screw terminals on this class of accessory. Use ferrule-ended stranded wire at that strip length to avoid stray strands shorting to adjacent slots.","metaTitle":"Siemens 3VA9908-0BB21 SENTRON Undervoltage Release, 48 V AC","metaDescription":"Siemens 3VA9908-0BB21 SENTRON undervoltage release accessory for 3VA1/3VA20-3VA25 breakers. 48 V AC 50/60 Hz, 2 VA coil, 4 kV surge rating. Active production, sourced to order. Req","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":"3VA9908-0BB21","Height":"65.1 mm","Maximum":"16","Minimum":"20","Accessories":"Auxiliary release","description":"UNDERVOLTAGE RELEASE 48 V AC 50/60HZ ACCESSORY FOR 3VA1 and 3VA20 up to 3VA25","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"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/acf31171a4ba8160ee2f5bd71fb142e0.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=364423&mlfb=3VA9908-0BB21"},"ai":{"faq":[{"question":"Where can I buy 3VA9908-0BB21 and how do I get a price?","answer":"This part is sourced through independent distribution channels and quoted to order. Submit an RFQ — availability and current pricing are confirmed at quote time."},{"question":"What compliance documentation does this brand provide for 3VA9908-0BB21?","answer":"As a Siemens SENTRON accessory, the 3VA9908-0BB21 carries the standard CE marking for the European low-voltage directive. RoHS and REACH declarations are typically included with the product documentation. For specific certificates (UL, CSA), verify against the breaker assembly's overall listing."},{"question":"What is 3VA9908-0BB21's listed depth (28.8 mm) on this component line?","answer":"The depth is 28.8 mm, measured from the mounting surface to the outermost point of the housing. Combined with a width of 25.7 mm and height of 65.1 mm, it fits within the standard accessory slot on 3VA1 and 3VA20–3VA25 breakers without protruding beyond the breaker envelope."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3VA9908-0BB21","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/3VA9908-0BB21 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}}