HANDBOOK REQUIREMENTS - Central Maine Power Company

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In cases not meeting the preceding specifications, the
customer shall provide a Company approved transformer vault or
yard. Additional information will be furnished upon request.
Padmount transformer foundations must be supplied by
the Customer and pad designs must conform to Company
specifications to ensure interchangeability with spare
transformers. See Illustrations No.s 23, 24, 25 and 26 in Section
XII.
Padmount transformer locations shall be graded for proper
drainage and that drainage shall be maintained by the customer.
In addition, the location must be readily accessible
by truck at all
times
without causing site damage.
A ¾ inch by 8 foot galvanized ground rod will be furnished
(available at the local Service Center) by the Company and
installed by the customer. It is to be located 6 inches in front of
the left front corner of the foundation. The ground rod should be
left 6 inches exposed above grade until all ground connections are
made and inspected. Prior to back filling around the foundation
base, the customer will furnish and install a bare #4 stranded
copper for grounding of the transformer. The conductor must be
of sufficient length (10 ft. of grounding conductor will be
required for single-phase and small (7’ x 7’) three-phase
installations, larger three-phase (9’ x 9’) or greater will
require 20 ft. of grounding conductor) to connect the
transformer neutral and ground to the ground rod. The conductor
will extend from the interior of the base, through the ground wire
hole (if available) or one of the cable holes (bond outs) in the wall
of the base, to the ground rod location. It is NOT to be installed
on
top of the base or slab (foundation) such that the transformer or
slab will bear directly on the conductor.