Weather forecasters and climatologists tell us storm frequency will increase in both severity and magnitude as our planet suffers the worsening effects of global warming. Debunking these predictions has become more difficult as the hard evidence becomes unignorable-take this most recent blizzard that stretched across the Northeast for three full days dumping more than 24 inches of snow in its wake. In the path of these storms lie our beautiful homes on beautiful tree-lined streets. As neighborhoods continue to age, so do the trees, many of which are now in the zenith of their life. No longer capable of supporting the tons of massive tree limbs suspended above our power lines, these full growth trees haplessly await the next climatic storm to roll in.
Whether a tree falling in the woods is heard by a bear or not is inconsequential when one considers the inevitable twofold consequences, power outages, and exposed electrical hazards. Portable and stand-by generators will help get us through power outages but do we really know how to recognize the downed power lines and what constitutes a safe distance?
Before discussing the dos and don’ts of downed power lines, a layman’s understanding of voltage and its ‘potential’ to cause shock and injury are worthy of a quick look.
Basically, electricity as we use it, is the flow of electrons (flow is known as current) along the length of a conductor. Human exposure to this voltage is known as shock. Shock can be as little as a minor tingling to a jolt to the nervous system to a condition as serious as being unable to let go and extricate oneself from the circuit-without outside intervention, this condition can be fatal. All characteristics of electrical shock center around the concept of potential, more specifically the difference of potential, because without it, no current can flow and thus no injury can occur. If all things are of the same voltage, there is no difference of potential and therefore no possibility of current flow nor cause injury. However, when a higher potential and a lower potential exist (a live conductor being the high potential, the earth being the low potential) and we unwittingly place ourselves between them, now the stage is set for the flow of electrons through a conductor (the body although a poor conductor is one nonetheless).
A downed power line presents just such a high and low potential. As the escaping energy in the form of electricity leaves the cable and enters the ground, it radiates outwards symmetrically. As it travels through the earth, the voltage begins to dissipate due to the resistive nature of rock and soil. What was a very ‘high potential’ where it entered the earth becomes a ‘lower potential’ as it emanates outwards in a series of ever-lessening rings. It is conceivable for a person to stand perfectly still within one of these rings and feel only a mild or no shock at all due to the equal potential. However, straddle two differing rings of potential and the difference between the two could be deadly. This form of shock is known in electrical safety as ‘step potential’ and many that experience it do not live to relay their experience.
Not all downed power lines are arcing, hissing, or thrashing around writhing wildly-some appear to be perfectly harmless. Our senses are of no use to us here. We must supplement what appears to be a safe scene with learned information.
Following these simple tips may help you and your loved one should you ever find yourself exposed to this ‘potential’ danger.
There are many similar looking conductors on a telephone pole, from CATV (at the bottom) to telephone (above cable) to secondaries (house voltage) to primary voltage at the top (transmission). If you come across a downed utility wire of any kind, always do the following:
· Assume it is energized and stay as far away as you can. Energized lines can charge the ground near the point of contact. If you come upon a downed line of any kind, stay at least 35 feet away (about the length of a bus). However, it is not safe to assume harmful voltage has dissipated down to safe levels at 35 feet. This is only a rule of thumb. Stay back!
· Do not attempt to rescue a person or pet.
· Call 911 or the utility serving the location. Leave everything to utility professionals and emergency personnel.
· Do not drive over downed power lines. Even if they are not energized, downed wires can get entangled with your vehicle and cause further damage.
· Stay in your car. If a power line falls on or near your vehicle, do not exit until you know for sure that the line is de-energized. Follow the directions of responding emergency personnel.
· If you must evacuate, jump away and land with both feet together. Do not touch the vehicle while stepping on the ground, as this can create a path for electricity to run through you. Keeping your feet together to minimize step potential in the interest of equal potential.
· Shuffle away to safety. Keep your feet together and take small, shuffling steps until you are at least 35 feet away. Taking larger steps could straddle a differing potential and create a path for electricity to run up one leg then out the other.
At Lippolis Electric, electrical safety is our primary concern. Educating our customers is just as important to us as educating our workforce. For more information feel free to contact us at 914-738-3550.
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Lippolis Electric, Inc. | 2538 Route 22, Pawling, NY 12564 | 845-855-1426 | lippoliselectric.com