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Thursday, September 22, 2016
Question:
Where in the code, does it tell about keeping voltage in a vault a part and what you can support the cable on.
William Hunter
A
Answer:
Hey William thanks for your question. Dry-type transformers over 35,000 volts must be installed in a vault as stated in 450.21(C). The requirements for vault construction are in Article 450 Part III. Some other specific requirements for vaults are in 110. 31 and Part V of Article 110. The term vault is used many other times in the NEC, often as allowing conductors and equipment to be located in them.
Sections 110.70 and 110.74 have some rules for conductor installations that are related to vaults. Supporting rules are in 300.11 and there are additional rules in the.30 section of the applicable wiring method article in Chapter 3.