Laserfiche WebLink
O 1997 Portland General Electric. All rights reserved, <br />2. Working space around equipment with live parts when energized. (See NEC 110-32:}~ <br />Clear area with minimum dimensions - 6 1/2 feet high, 3 feet wide, and 5 feet <br />deep. <br />• Room for operation of tools such as hotsticks. <br />• Able to remove one piece of equipment without having to move other unrelated ~ <br />equipment. <br />3. Minimizing amount of vault wiring to: <br />• Reduce cost ard labor. <br />• Reduce exposure of wire to faults. <br />• Reduce congestion. <br />4. Allowance for air circulation around equipment for cooling. Generally keep <br />transformer(s) one to two feet from vault walls. Do not stack transformer(s) into the <br />corners unless air circulation is adequate in the corners. <br />5. Location of customer's gear. Locate transformers near customer's panels, if possible. <br />Since vaults for commercial buildings generally have no live exposed parts, they tend to be <br />smaller than vaults in residential high-rise buildings. A commercial building may have a pad- <br />mounted transformer enclosed in a vault instead of submersible-type transformers with dead- <br />front primary bushings. For installations where the necessary door width and conduit can be <br />supplied, a submersible-type transformer is the simplest form of installation. <br />The actual vault dimensions are usually worked out with the building architect. A vault should <br />be sized conservatively large to allow room for future load growth & proper cooling without <br />major remodeling. Several layouts are possible in commercial vaults, and a lot of flexibility will <br />allow changes to be made later during construction, if needed. Considerations should be <br />given to deadfront secondary, internally fused transformers, and submersible transformers. <br />Figure 2 is a typical layout for a commercial building Class A vault. <br />PGE PROPRIETARY MATERIAL - THIS INFO IS BASED ON ASSUMPTIONS 8 CRITERIA WHICH MAY NOT BE VALID OUTSIDE TNE PGE ELECTRIC SY5TEM - FOR INTERNAL USE ONLY <br />UNDERGROUND BUILDING CLASS A <br />VAU LTS <br />UNDERGROUND <br />P.G.E. CO. STANDARD <br />X I DESIGN ~ ~ CONSTRUCTION <br />I T8D STANDARDS ~ <br />DATE 08-09-96 <br />LD-310-07-06 <br />S{-a T""y~:w.ny A'~~ _. . <br />~=Back --Nfenct - Close~~ - <br />