Police, firefighters and EMTs are usually the first to arrive on the scene of an emergency and can face great risk of electrical hazards. This information will help first responders recognize these risks and manage conditions to avoid life threatening situations for them and the people they serve.
Electric utility industry
Utility employees will respond to emergencies involving electricity. A customer may call because of a power outage, or responders at the scene may make the request. One thing is certain; no one is better trained and skilled to handle an electrical emergency than an electric utility company employee. When possible, it is best to wait until the utility representative arrives at the scene to deenergize (isolate, test and ground) the power line to an emergency location.
Power lines can be deadly – what you know could save your life
Knowing how electricity works and travels helps to understand that, without serious caution, it can be deadly.
How electricity works
Electricity leaves the power plant and is sent over high–power transmission lines on tall towers. The very strong electric current from a power plant must travel long distances to get where it is needed. Electricity loses some of its strength (voltage) as it travels, so transformers, which boost or “step up” its power, must help it along.
When electricity gets closer to where it will be used, its voltage must be decreased. Different kinds of transformers at utility substations do this job, “stepping down” electricity’s power. Electricity then travels on overhead or underground distribution wires to neighborhoods. When the distribution wires reach homes or businesses, another transformer reduces the electricity down to just the right voltage to be used in appliances, lights, and other things that run on electricity.
A cable carries the electricity from the transformer to the house through a meter box. The meter measures how much electricity is used by the people in the house. From the meter box, wires run through the walls to outlets and lights. The electricity is always waiting in the wires to be used.
Electricity travels in a circuit. When an appliance is switched on, it completes the circuit. Electricity flows along power lines to the outlet, through the power cord into the appliance, then back through the cord to the outlet and out to the power lines again.
Electricity always seeks a path to the ground. All electrical contact incidents occur when a person accidentally becomes part of electricity’s pathway to the ground. Making contact with underground power lines can be just as hazardous as making contact with overhead lines. Contacting underground lines can occur by digging in, or if the line in the ground becomes exposed during the emergency.
Electricity travels at the speed of light. It is made up of electrons that flow rapidly in an electrical current. Electrical current moves so quickly that it can travel the distance of the world’s circumference 7.5 times per second. Electricity is attracted to materials known as conductors that allow it to flow readily. Some conductors include:
- Wet Objects
- Trees (because they contain moisture)
- Humans and animals (bodies also contain moisture)
- Dirt on electrical insulators
- Heavy smoke
Touch potential occurs when contact is made with a live wire or an object that is energized. These can include objects like energized vehicles, fences, metal buildings and tree branches. Also, objects not normally conductive can become hazardous when contaminated by water, dirt, ash, smoke, fire retardant or other substances.
Step potential involves a downed wire or other source of high voltage and the subsequent dissipation of electrical voltage current through the ground. The voltage circulates out from the source at the point of contact like rings when water ripples from a stone that is thrown into a pond. The highest voltage is at the source which then produces gradients of lesser voltages. While rushing in to help a victim, if steps are placed in areas on the ground with two different voltages, current can flow through the body and may result in injury or death.
Responders should always be conscious of the possibility of touch and step potential. They are the most common ways in which responders can be injured or killed when electricity is involved.
When electricity is involved in an emergency situation, extreme precautions need to be taken. Any time electrical wires are involved, always consider them to be live or energized. This will help keep you from becoming a victim yourself. Remember electricity does not have an odor and it is not visible.
Caution begins with the approach to the accident site. Be aware; take a good look around before even getting out of your vehicle. There may be damaged wires capable of falling, even if they are away from the accident scene. Park away from the incident, at least the wire span of two utility poles, and preferably on the other side of the road.
Make careful observations as there may be wires tangled in fallen trees that are hard to see, or a wire may be touching a fence or other object. Never believe that a wire is insulated, it may appear coated but will not protect you against electric shock.
Never attempt to move a wire, even if it appears to be a telecommunications wire because they may be in contact with an energized wire. “Hands off all wires,” is always the policy. Don’t bet your life on being able to tell the difference. Be aware when approaching a downed line that the ground may be energized. For your safety, a good rule of thumb is to stay at least 30 feet away from all distribution lines and 100 feet away from all transmission lines that are knocked to the ground. Call 1-888-221-7070.
Do not attempt to rescue someone that has made contact with a downed line unless you know for sure that the line has been deenergized.
The utility company will confirm this for you.
Vehicle rescue from downed electric wires
If you respond to a vehicle accident and the operator of the vehicle is inside, instruct the driver and all passengers to remain in the vehicle until the electric utility company confirms that the lines have been de-energized. If there is no immediate danger, this is the safest place for the occupants of the vehicle.
In situations where occupants require urgent medical attention, other actions should be taken. If the driver is capable of operating the car and it is safe to move the vehicle away from the downed wire, instruct them to do so. Always watch that wires are clear of vehicle axels so they do not become entangled and create a more dangerous situation.
Be aware of coil memory. If a wire is pinned by a vehicle, when it is released it will coil back towards where it is connected. Keep a safe distance, at least 100 feet, and stay clear of the path that the wire may take when it recoils.
If the vehicle is on fire and it is necessary for the occupants to leave, they must be able to jump clear of the vehicle without making contact with the car and the ground at the same time. Instruct them to avoid any wires that might be on the ground, fold their
arms across their chest and jump carefully with both feet together so they don’t fall back against the car or touch the ground and the vehicle at the same time. Once they have cleared the car, they should shuffle or hop with both feet together making contact with
the ground at the same time, until they are at least 100 feet from the accident site.
One important note of caution: Responders must remember that instructing victims to exit a charged vehicle is extremely dangerous and must only be used when all other options are exhausted.
Electrical substation emergencies
Never attempt to enter a substation or power plant until given the “okay” by electric utility personnel.
SIX ELECTRICITY MYTHS THAT CAN KILL
- Myth: Power lines are insulated.
The majority of power lines are not insulated even though they may look like they are. Even the ones that are, could have lost insulation in a storm or degrade over time. No line is safe to touch or approach too closely, ever!
- Myth: The line is safe because it’s not high voltage.
Actually, voltage is not what kills, amperage is. Currents above 75 milliamps (mA), which is 1/1,000 of 1 amp, can cause fatal heart irregularities. A standard 60 watt light bulb draws 0.5 amps.
- Myth: A fallen wire will shut off.
Don’t count on it! If the wire lands on a poor conductor the wire will not short circuit and the wire will remain energized.
- Myth: A live wire will make sparks when it falls.
Not always, when a wire falls to the ground and makes firm contact, it will often make NO noise or sparks.
- Myth: Wood is not a conductor.
False, wood is just a poor conductor. When wet, wood is a much better conductor, so be careful.
- Myth: Rubber gloves and rubber shoes insulate.
Only 100% pure rubber insulates against electricity. Household gloves and shoes are not made of pure rubber and, if there is any dirt, contamination or holes (even undetectable) all bets are off.
Emergency Response Tips
- Park on the opposite side of the street, at least two pole spans away
- Pay attention to damaged adjacent poles, wires or structures that could be potential hazards
- Wait for electric utility company verification that a downed line has been de-energized
- Refer the cutting of power lines and pulling of meters to electric utility personnel
- Consider ALL downed lines to be energized and keep a safe distance, at least equal to the height of the pole
- Remember potential conductors of electricity (water, metal, ash, heavy smoke, wood)
- Ensure there is no longer contact between the victim and any electrical current before attempting a rescue
- Disconnect power at the main circuit breaker
- Park emergency vehicles under power lines
- Apply solid-stream water applications or foam sprays on or around energized equipment or lines
- Pull meters or use tools to cut power lines, climb poles or towers
- Attempt to enter a substation or power plant until given the “okay” by utility personnel
- Situate command posts or staging areas within a transmission-tower clear zone
- Attempt to remove a tree that has fallen on a power line
To report a downed wire, broken pole or any damage to the electric system, please call Rocky Mountain Power at 1-888-221-7070.
Call 1-800-375-7085 or email email@example.com to order free laminated 4.5” x 6.5” cards with tips and phone numbers for emergency responders.
For more safety information, including electrical safety videos for first responders, please visit rockymountainpower.net/first responder.