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Tuesday, January 11, 2022
Question:
Hello CQD,
Are enclosures of equipment installed for and supplied by ungrounded A/C systems required to be marked to indicate that? What NEC rule applies.
Thanks for any help you can provide.
Bill Cole
A
Answer:
Hi Bill,
Section 250.21(C) indicates that ungrounded systems shall be legibly marked “Caution: Ungrounded System Operating — _____Volts Between Conductors” at the source or first disconnecting means of the system. The marking shall be of sufficient durability to withstand the environment involved.