Explanation: As noted in Sec. 450.13(B) of the 2020 NEC, transformers placed in hollow spaces must be no larger than 50kVA. Lupacchino is a senior design engineer with Gaylor Electric, Inc. in ...

Learn how to test a transformer: insulation resistance, TTR, winding resistance, polarity, continuity, and dielectric checks.

Explanation: In the 2020 NEC, a new sentence was added to the end of Sec. 450.9. It reads as follows: "Transformer top surfaces that are horizontal and readily accessible shall be marked to prohibit ...

Part 1 of this three-part series laid out an overview of a proposal to create a numerical health index and establish a practical program for power transformer maintenance. Part 2 breaks down each of ...