77.509—Transformers; installation and guarding.
(a)
Transformers shall be of the totally enclosed type, or shall be placed at least 8 feet above the ground, or installed in a transformer house, or surrounded by a substantial fence at least 6 feet high and at least 3 feet from any energized parts, casings, or wiring.
(b)
Transformer stations shall be enclosed to prevent persons from unintentionally or inadvertently contacting energized parts.