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Code Quiz: Transformer Disconnecting Means


Fill in the blanks with the appropriate answer.

When installing a transformer (such as a 75kVA unit), the disconnecting means for this piece of equipment shall be _________, and the location of the disconnecting means shall be ______ marked on the transformer.


A. approved / properly

B. lockable / field

C. suitable / suitability

D. lockable / factory


Answer: B

As noted in 450.14 of the 2011 NEC, "Transformers, other than Class 2 or Class 3 transformers, shall have a disconnecting means located within sight of the transformer or in a remote location. Where located in a remote location, the disconnecting means shall be lockable, and the location shall be field marked on the transformers."

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at [email protected].

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