MIL-HDBK-1025/10
7.10.1.2 Over, Under, or Across Energized Lines. When wires are strung and sagged
over, under, or across conductors carrying a voltage of 5,000 volts or less, personnel handling the
wire should wear rubber gloves and use other necessary protective devices. Conductors carrying
more than 5,000 volts should be positively and constantly grounded during the stringing
operation. As soon as the wire is ready to be deadended, it should be grounded with standard
grounding devices.
7.10.2 Other Work Precautions Affecting Aerial Lines. Electrical charges may
appear on the line from a lightning strike or from induced static charges from a very dry
atmosphere. Discontinue operations when there is any indication of lightning in the surrounding
area.
7.10.2.1 Fallen Wires. All personnel should look for fallen wires. A worker finding a
fallen wire will stand by it to protect all street and highway traffic and pedestrians from the
hazards. As soon as possible, another worker should be directed to telephone the facilities
engineer or the appropriate superintendent to have the wire de-energized. The worker finding the
fallen wire should not leave until instructed by the supervisor in direct charge.
7.10.2.2 Fire. All electric lines close to a fire should be de-energized immediately to
protect the firemen. The electric lines should not be re-energized until all danger has been
removed. Where electric lines were located close to the fire, the electric lines, ground wires, and
guying should be inspected carefully. Inspect insulators for cracks and crossarms and poles for
charring before the electric lines are restored to service.
7.10.2.3 Vehicular Protection. Wires being strung along or across streets or highways
should be kept sufficiently elevated to eliminate vehicular collisions. The supervisor should
delegate a competent person to act as flagman. Traffic should be blocked when this line elevation
is not possible.
7.10.3 De-energized Line Grounding. Requirements for grounding of de-energized
lines are covered in Section 5. Other grounding requirements should be as follows:
7.10.3.1 Permanent Ground Wires. Permanent ground wires are installed to protect
workers. Remember that the metallic case, covering, or mounting support of any energized piece
of electrical equipment should be considered energized at full voltage if it is not properly
grounded. All permanent grounds should be installed in accordance with the requirements of the
NFPA 70, The National Electrical Code (NEC) or the ANSI C2, The National Electrical Safety
Code (NESC) as applicable.
a. Ground wires should be installed clear of all metallic line equipment (except that which
is normally grounded), hardware, or streetlighting fixtures.
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