Trees and electricity are both beneficial, but when the two come
together, problems arise. Add a third component, a human, and a life may
be in jeopardy.
It's a harsh reality that workers pruning trees near energized power
lines face serious hazards from contact with those lines
or related equipment. A worker's body may come into direct contact with
an energized line. Tools or other conductive
material, such as severed tree limbs, may touch the lines, resulting in
an indirect, but equally dangerous, contact. Either way,
the worker is exposed to electrical shock by becoming a path to the
ground between an energized conductor and grounded
equipment, tools, or trees or by becoming a path between two conductors.
The electrical current passing through the body can cause third degree
burns, irregular heart action, stoppage of the heart or the
stoppage of breathing. In addition, you may be exposed to thermal burns
or flash burns from arcing.
If you are trimming trees your first concern should be to protect
yourself from such hazards.
Before any work begins, the job site should be inspected to locate
overhead power lines and electrical equipment. If there
appears to be any conflict, contact the electric utility company so
measures can be taken to ensure a safe work environment.
Remember that the distance the tree is away from the energized lines can
be deceiving. In some cases, it may be just as
dangerous to trim a tree 10 to 20 feet from energized lines, as it is to
trim one much closer, because a long, large branch can
fall into the lines and conduct electricity back to the trimmer who
believes he has maintained an adequate clearance.
Unqualified individuals should never trim trees around energized lines.
Where electrical hazards exist, only qualified line
clearance tree trimmers should do the work. When climbing, climb the
side of the tree away from power lines. When tying in, the branch of the tree
selected for tying in should be over the work area, but located in such
a way that a slip or fall would swing the trimmer away from energized lines.
Ladders and aerial equipment, including insulated aerial equipment,
should not be placed in contact with electrical conductors.
If an aerial device does contact an electrical line or conductor, the
truck supporting the device and any other attached
equipment should be considered energized. Anyone touching the equipment
could be injured or even killed.
Safe Work Practices
Determine whether you and your crews can maintain the 10-foot safety
clearance from power lines required both by state and federal regulations.
Mechanized equipment should maintain a minimum 10 foot distance from
power lines and conductors rated at 50,000 volts or
less. This equipment includes load, cables, tag lines and any other
attachments. If the power line is rated more than 50,000
volts, the clearance should exceed 10 feet.
Consider these clearance requirements for work near overhead power lines
as your "circle of safety." These working
clearances are minimum safety clearances. Whenever possible, even
greater clearances should be maintained.
If your work is going to bring you closer than the above clearances
recommend, notify the electric utility company. No work should be
performed near energized conductors until danger of contact with those
conductors has been eliminated.
Inspect the work site carefully prior to climbing or working on a tree
to determine whether electrical lines pass through the
tree or within your reach or that of other workers. All lines on utility
poles should be viewed as possibly being energized, even if you think
they are cable or telephone lines.
Only qualified line clearance tree trimmers employed by or supervised by
the electric utility company and using approved insulated equipment
should remove branches hanging on energized power lines.
Underground Electrical Equipment
Workers should be aware of the location of ground mounted electrical
facilities as well as overhead power lines. Vehicles positioned for work
should be kept clear of this equipment. Damage to the equipment may
cause power outages and create electrical hazards for the tree workers.
When planting or removing trees, workers should be aware of any
underground utility cables buried in or near the work area.
In fact, in Louisiana, state law requires anyone planning on doing
excavation work to determine the location
of all underground facilities. The utility companies will come out and
mark all underground wire locations free of charge. You must "Call
Before You Dig" forty-eight hours prior to digging. This is a free call
in Louisiana. The telephone number is 1-800-272-3020. The law also
requires no excavation work to start until all utilities have
been marked or determined not to be in the digging area. If you do not
call before you dig and you cut the lines, you may be billed for the repairs.
If you do find underground cables or wires do not leave them exposed.
You should call the utility company to report the exposed line.
Spraying operations near energized electrical wires or equipment may
create safety problems. Spraying directed into
overheated lines may damage equipment or cause arcing between wires.
Electricity also may be conducted down the hose stream, creating a
hazard for workers.
Strong winds, storms, ice, or unintentional contact with equipment may
cause trees or tree limbs to fall into power lines. This may cause wires
to break and fall to the ground. Should this happen, call 9-1-1 and
notify the electric utility company immediately.
A fallen wire can create hazards for workers and the general public.
Objects touched by a fallen wire, fences, vehicles,
buildings or even the surrounding ground must be considered energized
and should not be touched. It is impossible to tell
simply by looking whether a downed wire is energized. Consider all
downed wires energized and dangerous until the electric utility
personnel notify you otherwise.
Where a power line has fallen across a vehicle, occupants should remain
within the vehicle. If they must leave the vehicle
because of a life-threatening situation, such as fire or potential
explosion, they should jump clear of the vehicle without
touching either the vehicle or wire and the ground at the same time.
Once clear of the vehicle, they should shuffle away, taking small steps
and keeping both feet in contact with the ground.
Remember...electricity can be transmitted from the victim to you. If a
switch is accessible shut off the power immediately.
Otherwise, stand on a dry surface and pull the victim away with a dry
board or rope. Do not use your hands or anything metal.
Use a CO2 or dry chemical extinguisher to put out an electrical fire.
In an emergency involving power lines or electrical equipment, call
9-1-1 and the electric utility company immediately.
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