The specification covers design manufacture, testing packing and delivery of 3 phase 50 Hz, Dry Type (VPI) distribution transformer of ratings 100, 200,315,630,1000,1250, 1600 And 2500 kVA, 11/0. 433 KV ( Indoor and Outdoor type) Natural Air Cooled (ANAN). Building on years of experience in engineering and design of transformers comes a product that is guaranteed to provide high-efficiency in an economical package. These units are designed to the latest Industry Standards, and are CSA and UL certified. Transformers must qualify to high-efficiency. e provided in the Distribution Box will be as per Emplo e as per IS:13411 (amended upto date), no separate enclosure i required. Isolator Base should withstand the breaking capacity of 80 kA. To extinguish the arc immediately in iso ators, in each phase arc-chutes with minimum 12 strips ype. The. sign special regulations. design free-breathing or hermetically sealed transformers Liquid-filled. Dry-Type Transformer Family2. 1 DOE 2016 Energy-Efficient Transformers Product Description. 1 Specifications and Dimensions for Wood Poles, ANSI C57.