10 Minute Training
IRMA “Safety Basics” Series
Downed Power Lines:
Protecting First Responders from Electrical Hazards
SUPPLEMENTAL MATERIALS
Training Officers: The following (4) documents can be used as class hand-outs and/or as posters on this topic.
10 Minute Training
IRMA “Safety Basics” Series
Downed Power Lines:
Protecting First Responders from Electrical Hazards
QUIZ
Instructor’s Copy
Training Officers can administer the following quiz after completing the 10 Minute Training to reinforce key concepts.
Name: ___________________________________________________
Circle the best answer for the questions below.
1. What distance perimeter should be established around a downed power line?
a. 10 ft.
b. 20 ft.
c. 35 ft
d. 50 ft.
2. A downed power line that is not sparking is safe to move.
a. True
b. False
3. If a power line comes down on top of a vehicle the driver should:
a. Immediately exit the vehicle
b. Stay in the vehicle until ComEd de-energizes the line
c. Drive away from the line if it’s safe to do so
d. Either B or C above
4. Electrical current will not travel through the ground from a downed power line.
a. True
b. False
5. You can tell the difference between a high voltage power line and other overhead utility lines.
a. True
b. False
Answers: 1 - c.; 2 – b.; 3 – d.; 4 – b.; 5 – b.
10 Minute Training
IRMA “Safety Basics” Series
Downed Power Lines:
Protecting First Responders from Electrical Hazards
QUIZ
Name: ___________________________________________________
Circle the best answer for the questions below.
1. What distance perimeter should be established around a downed power line?
a. 10 ft.
b. 20 ft.
c. 35 ft
d. 50 ft.
2. A downed power line that is not sparking is safe to move.
a. True
b. False
3. If a power line comes down on top of a vehicle the driver should:
a. Immediately exit the vehicle
b. Stay in the vehicle until ComEd de-energizes the line
c. Drive away from the line if it’s safe to do so
d. Either B or C above
4. Electrical current will not travel through the ground from a downed power line.
a. True
b. False
5. You can tell the difference between a high voltage power line and other overhead utility lines.
a. True
b. False
FactSheet
Working Safely Around Downed
Electrical Wires
Electrical hazards exist in some form in nearly all occupations. However, those
hazards multiply for workers involved in cleanup and recovery efforts following
major disasters and weather emergencies. One particular life-threatening danger
exists around downed and low-hanging electrical wires.
Safety First
Above all else, always consider all equipment,
lines and conductors to be energized. Be
cautious and if you notice downed wires or
damaged electrical equipment, contact
appropriate utility personnel. Remember
that circuits do not always turn off when a
power line falls into a tree or onto the
ground. Even if they are not sparking or
humming, fallen power lines can kill you if
you touch them or even the ground nearby.
Energy
Downed wires can energize other objects,
including fences, water pipes, bushes and
trees, buildings, telephone/CATV/fiber optic
cables and other electric utilities. Even manhole castings and reinforcement bars (re/bar)
in pavement can become energized by
downed wires. During storms, wind-blown
objects such as canopies, aluminum roofs,
siding, sheds, etc., can also be energized by
downed wires.
Backfeed
When electrical conductors are inadvertently
energized by other energy sources, backfeed
occurs. Some of those sources include:
• Circuit ties/switch points
• Lightning
• Generators
• Downstream events
Simply testing for energy sources is not sufficient since hazardous electrical events can
happen without warning. Ensure that proper
lockout/tagout procedures are always followed.
Rules to live by
• Do NOT assume that a downed conductor
is safe simply because it is on the ground
or it is not sparking.
• Do NOT assume that all coated, weatherproof or insulated wire is just telephone,
television or fiber-optic cable.
• Low-hanging wires still have voltage potential even if they are not touching the ground.
So, “don’t touch them.” Everything is energized until tested to be de-energized.
• Never go near a downed or fallen electric
power line. Always assume that it is energized. Touching it could be fatal.
• Electricity can spread outward through the
ground in a circular shape from the point
of contact. As you move away from the
center, large differences in voltages can be
created.
• Never drive over downed power lines.
Assume that they are energized. And, even
if they are not, downed lines can become
entangled in your equipment or vehicle.
• If contact is made with an energized power
line while you are in a vehicle, remain calm
and do not get out unless the vehicle is on
fire. If possible, call for help.
• If you must exit any equipment because of
fire or other safety reasons, try to jump
completely clear, making sure that you do
not touch the equipment and the ground at
the same time. Land with both feet together and shuffle away in small steps to minimize the path of electric current and avoid
electrical shock. Be careful to maintain your
balance.
This is one in a series of informational fact sheets highlighting OSHA programs, policies or
standards. It does not impose any new compliance requirements. For a comprehensive list of
compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal
Regulations. This information will be made available to sensory impaired individuals upon request.
The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.
For more complete information:
U.S. Department of Labor
www.osha.gov
(800) 321-OSHA
DOC 7/2005
Power Lines Can Create Additional Dangers for Emergency Responders
First responders must have the capacity to make good judgments, and that requires them to be well-versed in
potential dangers they may encounter at the scene of a public safety incident. In an attempt to protect the public,
members of the police and fire service should not jeopardize their own safety and that can happen quickly when
electric lines are involved.
Electricity can be an invisible killer particularly when overhead power lines have fallen and made contact with
vehicles or the ground. The wire may not be sparking or visibly indicating its lethal characteristics, however it can
energize other objects it touches, and also send a potentially deadly charge into the ground that will disable or
electrocute someone approaching the wire on foot.
Traffic accidents, high winds, ice storms, and other events can bring electric transmission and distribution lines
within range of pedestrians and vehicles, and first responders have the challenge of not knowing whether the wire
is energized. Emergency personnel trainers, in addition to utility professionals, always advise police and
firefighters to assume that a downed wire is energized.
First responders should communicate with utility company personnel as soon as possible so they can respond to
ensure the line is de-energized and it is safe for other emergency workers to perform rescue and recovery of any
accident victims, provide traffic control, and manage any other life-threatening situations.
The first responder to a traffic accident in which utility lines are either on the ground or on the vehicle faces two
separate possibilities of a deadly electric shock. One of them is known as a “step potential,” and the other is
considered a “touch potential.” In both cases the emergency responder puts him or herself in danger of becoming
a path for the electricity to move through one’s body and cause serious or fatal injuries.
The term potential, as used with electric current, indicates a difference in voltage; and since electricity flows from
higher voltage to lower voltage, a person whose body connects those two points will become the path for the
current to flow.
A step potential can seriously injure or kill someone who is walking toward or away from the point where an
energized wire makes contact with the ground. As the electricity flows through the soil, which has resistance, the
voltage dissipates the further it goes. By striding across the affected area, an emergency responder could have
each foot in different voltage zones, and a fatal charge could travel up one leg and down the other to the area of
the lesser voltage.
A touch potential can similarly injure someone who is standing on the ground which may have a lesser voltage
than a vehicle which may be draped with energized wires. While the victims in such a vehicle are at a single
voltage, the difference between that and the voltage in the ground can be fatal to an emergency responder.
If you respond to an accident scene involving auto and downed lines, stay back and warn others to stay back.
Make sure the occupants of the car stay inside until the utility has arrived to de-energize the lines. In a rare
circumstance, the vehicle may catch fire. The only way the occupants can safely exit is to jump free and clear
without touching the vehicle and ground at the same time. Advise them to jump and land with feet together, then
hop away to safety.
Source: Energy Education Council, 2011.