According to OSHA, electrocution is one of the leading causes of death each year in the construction industry. Electrical accidents play a role in many trade-specific fatalities, affecting a variety of occupations, including tree trimmers, linemen, electricians and others.
One of Connexus Energy’s safety goals is to increase awareness and educate children, teens, and adults about electrical hazards at work, home, and play. One of the ways we are
increasing awareness and saving lives is by educating our community with our High Voltage Electrical Safety Demonstration.
Connexus Energy created a custom-built, 7,200-volt safety demonstration unit back in 1994. Over the years, it has been updated and perfected to meet the training needs of fire fighters, utility workers, and safety camps for children. We have worked hard the past 23 years to reach our community and surrounding counties to educate people on the dangers of electricity.
HIGH VOLTAGE
Each presentation starts with grabbing the audience’s attention by putting an aluminum ladder onto the overhead power line, creating a 7,200-volt arc. Instantly, a flash and string of fire between the ladder and overhead line are clearly visible. With an average of one degree per volt, this arc is burning the air at around 7,200 degrees. In comparison, a typical house fire burns at a temperature under 1,000 degrees Fahrenheit. Our presenters are protected from electrical shock by using a “hot stick,” which is an insulated pole made of fiberglass. The hot stick used during the demonstration is rated to withstand 100,000 volts per foot. This arc is a visual reminder for people to look up and be aware of power lines before setting up ladders, scaffolding or tall signs.
Next in the presentation is demonstrating the arc that a kite string or fishing line can produce. Just like a bird sitting on a wire, if the kite string only touches one line, nothing detrimental happens. As soon as the string touches both overhead lines at once, creating
a path down to the ground, ZAP! Another flash and this time, literally, a string of fire. The arcs created travel at the speed of light and you cannot react quickly enough to escape electrical shock. Without the hot stick between the presenter’s body and the kite string, it could be fatal. Without the hot stick, the string would contact the overhead cable and the electricity would flow down the string and into the body. We inform the audience that electricity is always trying to get to the ground, and it will take any path to get there. Find
an open space for children to fly a kite and look up before casting your fishing line.
Few audiences forget what happens next. They are shown a thick rubber glove that our linemen use daily while working on energized power lines. We put a hotdog inside the glove and use the hot stick to drag the hotdog-filled glove along the power line. Nothing happens. Our presenter then pokes a tiny pinhole in the glove and puts the glove back onto the overhead cable. A 7,200-volt arc is present within seconds. The remnants of the black charred hotdog are shown to the viewers. This hotdog represents someone’s body, skin on the outside with meat and water on the inside. Faster than anyone can react, electricity entered the hotdog and used it as path to the ground, frying it from the inside out.
W e also place a hotdog near a mannequin’s heart. Again, this hotdog acts like your body,
meat and water inside along with an outer layer of skin. An antenna is linked to the mannequin’s body and the hot stick lifts the antenna into the overhead wire. The antenna arcs on the line while, simultaneously, the hotdog near the mannequin’s heart smokes and bursts into fiery pieces. This makes it simple to see how easily a roofing contractor, or anyone, could make one wrong move near overhead lines and have it turn disastrous.
One of our last tips to the audience is explaining what to do if their vehicle runs into a utility pole and wires fall down. This also goes for dump trucks, backhoes, cranes, and garbage trucks that may make contact with overhead lines. The safest place to remain is in the vehicle and to keep others away. It could be fatal for anyone who touches a vehicle and the ground at the same time. Even if lines aren’t arcing, they could still be energized. A common misconception people have is that the tires will insulate them. If the vehicle starts on fire, you may exit the vehicle by opening the door and jumping out. Be careful not to touch the ground and the vehicle at the same time. Land on both feet and hop or shuffle away. Taking a step or spreading your legs puts you at risk for step potential, which occurs when the ground is energized at different voltages; the electricity has the potential to travel up one leg and out the other side of your body.
While our demonstration focuses on overhead lines, there is also a real danger associated with buried underground lines. The same consequences outlined above can happen when digging into an underground line. In Minnesota it is a state law that anyone digging by mechanical means must contact Gopher State One Call to request underground utility locates before excavating.
LOW VOLTAGE
While high voltage arcs are shockingly attention-grabbing, our demonstration also educates on electrical safety with lower voltages. We use low voltage electricity every day; most household outlets are 120 volts, while some larger appliances may be fed by 240 volts. Our demonstration presenters create low voltage sparks on a metal plate and relate that to sticking a fork into a toaster. Even 120 volts is enough to stop your heart.
The presenters go on to demonstrate the safety features that GFI outlets have over regular outlets. They show viewers what a bad extension cord looks like and how your body can contract onto a damaged cord, making you part of the electrical circuit. It is important for everyone to understand that safety precautions must be followed around low-voltage
electricity, especially since daily use can make it easy to overlook.
The Connexus Electrical Safety Demonstration is a full-scale, self-contained unit that is driven to each event. The demo unit is transported inside a trailer and is easily rolled out at each presentation location. There is a stationary generator inside the trailer and a
transformer that is rolled off with the presentation unit. No outside power sources are needed. The generator inside the trailer generates 240 volts, which feeds into the secondary side of a 15 KVA transformer located underneath the demo unit. The transformer then outputs 7,200-volts from its primary side, allowing us to create an arc. In real life environments, electrical power lines are always energized and dangerous. The demo unit, however, is only energized when a button is pressed to close the relay and complete the circuit.
Currently, this is the only demonstration unit of its kind in the state of Minnesota. In 2016, Connexus Energy presented 86 safety demonstrations to more than 3,600 people. Our typical audience includes electrical line worker students, electric cooperatives, police and fire departments, tree trimmers, excavators, and local community events.
Brianne Wodicka is the Public Safety & Claims Coordinator with Connexus® Energy. She can be reached at Brianne.Wodicka@connexusenergy.com.