MIL-HDBK-1025/10
b. Rubber gloves or hot sticks should be used when installing a pole-type transformer.
First connect the primary leads from the transformer to the primary cutouts; second, make sure
that secondary leads from the transformer are in the clear; third, make connections from cutouts
to primary line; fourth, close primary cutouts; fifth, make polarity tests on secondaries and
connect permanently. When removing transformers, open cutouts and disconnect secondaries to
prevent danger of "backfeed".
c. Where one or more transformers feed into a common secondary or are paralleled on
the low-voltage side, caution should be exercised in re-fusing, as the higher voltage terminals will
be energized by stepping up the secondary voltage that is supplied by the other transformer.
7.12.4.4 Aerial Inspection and Maintenance. Only "Qualified Climbers" should be
allowed to climb poles to inspect and test pole-type transformers. Never stand on or otherwise
contact transformer cases, while working on or near energized circuits.
a. Before changing or replenishing oil, all energized connections to transformers should
be disconnected from all live circuits.
b. When opening transformers, do not use lighted matches or open flames of any kind.
7.12.4.5 Aerial Fusing. When installing fuses, workers should be careful to avoid contact
with any live lines, or with any grounded surfaces (grounded lines, the casings of grounded
transformers, streetlighting fixtures, signal lines, signal equipment, the metal sheathing of cables,
metal conduits, span wires, and guy wires).
a. Before installing fuses in new cutouts, replacing fuses, or opening disconnects, workers
should protect their eyes by wearing goggles and faceshields. They should not use their arms to
protect their eyes and faces from any flashes or arcs that may occur. It is mandatory for the
workers to wear rubber gloves or to use a "hot stick" as appropriate to the voltage level.
Workers should secure themselves to the pole with their safety harnesses.
b. When fuses are taken out of the circuit they should be removed entirely from the fuse
enclosures or cutouts.
c. In phasing out a transformer or in testing it for polarity, small size fuses should
preferably be used.
7.12.4.6 Aerial Service Connections. Do not string service wires from a transformer
pole if it is at all possible to install them at some other location. Service wires should never be
installed on transformer poles, unless a minimum separation meeting code requirements can be
maintained between the service wires and the energized primary conductors or apparatus.
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