{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3VA9978-0AA12","brand":"Siemens","brandSlug":"siemens","productSlug":"3VA9978-0AA12","canonicalUrl":"https://aoctrl.com/siemens/3VA9978-0AA12","factsUrl":"https://aoctrl.com/api/mcp/products/3VA9978-0AA12","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON, auxiliary switch, changeover contacts type HQ (7 mm), 6 A thermal current, for 3VA4/5/6 circuit breakers, order code 3VA9978-0AA12.","salesMarkdown":"The Siemens 3VA9978-0AA12 is a SENTRON auxiliary switch with changeover contacts (type HQ, 7 mm contact gap) designed as an accessory for 3VA4, 3VA5, and 3VA6 molded-case circuit breakers. It provides remote status indication — open, closed, or tripped — from the breaker's internal mechanism. The thermal current rating of 6 A sets the continuous-carry capacity through the contacts; the actual switching capability depends on the load type and voltage, defined by the utilization categories. For AC control circuits, the switch handles 6 A at 12–240 V under AC-12 duty (resistive loads like pilot lights and relays), and 3 A under AC-15 duty (solenoid valves and contactor coils — the inductive inrush matters). For DC control circuits, DC-12 (resistive) is rated 6 A at 12 V, 4 A at 24 V, 2 A at 48 V; DC-13 (solenoid with significant inductance) drops to 1 A at 12 V, 0.8 A at 24 V, and 0.4 A at 48 V. The DC-13 ratings are the limiting factor for any DC coil or valve: at 24 VDC, the switch can interrupt 0.8 A, so verify the load's inrush and holding current against that ceiling. This auxiliary switch clips into the accessory slot on 3VA4/5/6 breakers — no DIN-rail space consumed, no separate wiring channel. The changeover contact (one NO + one NC) is wired via screw terminals; strip the conductor 15 mm (0.6 in) for proper insertion. It remains a cataloged accessory for the current 3VA platform.","metaTitle":"Siemens 3VA9978-0AA12 Auxiliary Switch, 6 A Thermal, for 3VA","metaDescription":"Siemens SENTRON 3VA9978-0AA12 auxiliary switch, changeover contacts (HQ, 7 mm), rated 6 A thermal, 3 A AC-15, 0.8 A DC-13 at 24 V. Active lifecycle, sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Circuit Breaker Accessories"],"specifications":{"Maximum":"16","Minimum":"20","Accessories":"Auxiliary switch","Stripped Length":"15 mm","Thermal Current":"6 A","lifecycle_stage":"current","Product Brand Name":"SENTRON","at AC-12 / at 12 V":"6 A","at AC-12 / at 24 V":"6 A","at AC-12 / at 48 V":"6 A","at AC-15 / at 12 V":"3 A","at AC-15 / at 24 V":"3 A","at AC-15 / at 48 V":"3 A","at DC-12 / at 12 V":"6 A","at DC-12 / at 24 V":"4 A","at DC-12 / at 48 V":"2 A","at DC-13 / at 12 V":"1 A","at DC-13 / at 24 V":"0.8 A","at DC-13 / at 48 V":"0.4 A","Degree Of Pollution":"3","Product Designation":"auxiliary switch","at AC-12 / at 125 V":"6 A","at AC-15 / at 125 V":"3 A","at DC-12 / at 110 V":"0.5 A","at DC-12 / at 250 V":"0.25 A","at DC-13 / at 110 V":"0.2 A","at DC-13 / at 250 V":"0.1 A","Overvoltage Category":"III","Stripped Length [In]":"0.6 in","Design Of The Product":"Accessories for 3VA circuit breakers","at AC-12 / at 220/240 V":"6 A","at AC-15 / at 220/240 V":"3 A","Surge Voltage Resistance":"4 kV","operating voltage / at DC / rated value / minimum":"250 V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$12.19","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=650503&mlfb=3VA9978-0AA12","alternativesUrl":"https://aoctrl.com/api/mcp/products/3VA9978-0AA12/alternatives.json"},"ai":{"faq":[{"question":"What are the key switching ratings for 3VA9978-0AA12?","answer":"Thermal current 6 A continuous. AC-12 (resistive) 6 A up to 240 V; AC-15 (inductive) 3 A up to 240 V. DC-13 (solenoid) 1 A at 12 V, 0.8 A at 24 V, 0.4 A at 48 V."},{"question":"Where can I buy 3VA9978-0AA12?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"What is the stripped length for wiring this auxiliary switch?","answer":"Strip the conductor 15 mm (0.6 in) for proper insertion into the screw terminal."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3VA9978-0AA12","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/3VA9978-0AA12 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}}