Quantcast Energized-line methods

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TM 5-684/NAVFAC MO-200/AFJMAN 32-1082
special insulating ladders. The insulating suit is
such as an aerial lift or an insulating ladder or
connected to the energized conductors to bring the
platform, and work with insulating tools and equip-
lineman to line potential.
ment.
(1) Policy. Departmental policy must be com-
c. Workers at line potential. Workers are bonded
plied with in the performance of "arehand" work. It
to the energized device on which work is to be per-
is essential that any personnel involved in "hot-line"
formed and are insulated from grounded objects and
work be thoroughly trained and experienced.
other energized devices that are at a different po-
Barehand procedures require a knowledge of all
tential. This is commonly known as the barehand
three methods covered previously and dictate mak-
technique and cannot be used by facility mainte-
ing periodic re-examinations of the worker's ability
nance personnel.
to safely use the barehand technique. A l l tools and
equipment must be in excellent condition and
4-64. Energized-line methods.
should be maintained solely for the purpose of per-
Most line maintenance utilizes insulated aerial lifts
forming live-line maintenance.
except where accessibility to the work area is impos-
(2) Qualified personnel. Consideration should
sible. Aerial lifts can be used for aerial inspections,
be given to having this type work done by a quali-
unenergized line maintenance, tree trimming,
fied contractor, unless the in-house personnel are
streetlighting and lamp replacement; but an aerial
fully qualified, adequately equipped, and perform
lift will most often serve as the elevated platform
this work frequently enough to maintain their pro-
for live-line maintenance.
ficiency.
a. Maintenance using rubber gloves and other
4-65. Live-line operations.
protective equipment. Work is done directly on the
lines using rubber gloves and other protective line
All live-line operations require special tools and
equipment such as rubber sleeves; rubber insulat-
equipment to perform the variety of work proce-
ing line hose and insulator hoods; and polyethylene
dures involves in hot-line maintenance.
conductor, insulator, crossarm, and pole covers. The
a. Tools and equipment. The tools and equipment
lineman may be standing on a climber gaff, pole-
used in live-line maintenance are made specifically
attached insulated platform, or insulated aerial lift
for this type of work. They are required to meet
for the line maintenance voltage levels (low-voltage
applicable acceptance test standards and they must
up to 15,000 volts medium-voltage) normally per-
be cared for and maintained to meet in-service stan-
formed by facility personnel. Utilities normally use
dards. Chapter 15, section V discusses these re-
rubber gloves and climbers up to 7,500 volts and
quirements.
platforms or lifts above this voltage to 17,000 volts.
b. Operations. The most common live-line main-
b. Maintenance using rubber gloves, other protec-
tenance operations are as follows:
tive equipment, and hot-line tools. This procedure is
(1) Replacing poles.
normally used for all primary distribution lines
(2) Replacing crossarms.
maintained by facility personnel.
( 3 ) Replacing insulators.
( 4 ) Washing insulators.
(1) Utilities use protective equipment and hot-
line tools for voltages of 17,000 volts to 26,500 volts
( 5 ) Cutting out and replacing live conductors.
and work from insulated platforms or lifts. For volt-
( 6 ) Tapping a hot line.
ages above 26,500 volts to 36,000 volts, utilities
( 7 ) Applying armor rods or vibration dampers.
require aerial lifts.
( 8 ) Phasing conductors.
(2) Approach distances and minimum tool in-
c. Procedures for replacing poles, crossarms, and
insulators. To replace any of these items requires
sulation distance requirements must be observed.
Rubber protective equipment comes in various volt-
that the conductors must be untied or unclamped
age classes. Never use equipment rated at less than
from their insulators and temporarily supported.
the maximum voltage involved.
(1) Poles. In overhead line maintenance, pole
replacement is usually the result of deterioration or
c. Barehand maintenance. Barehand mainte-
damage to the pole. The new pole should be set and
nance is done with the lineman at the same poten-
the wire tongs, saddles, and other tools needed to
tial as the line being worked on. A conductive liner
support the existing line while moving it to the new
of metal-mesh in the aerial lift (the basket shield-
pole should be provided. If the old pole must be used
ing) is brought to line potential using a bonding
to support any tools, temporary bracing may need to
lead. This lead, which is permanently attached to
be installed to strengthen the weakened pole.
the mesh, is hot-stick fastened to the energized line
(2) Insulators. The usual procedures in the re-
conductor. Barehand work can also be performed by
placement of insulators are as follows:
linemen in special conducting suits working from
4-34





 


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