Protection from Step and Touch Potential
At any time, things can happen such has downed power lines due to seasonal storms, vehicle/agriculture equipment accidents, broken poles, tree branches and fallen trees coming in contact with energized conductors. This article will cover hazards of working or being around fallen energized conductors and the unseen hazard of step and touch potential.
Step potential is the voltage difference between two points on the ground, such as a person’s feet. This can happen when current flows from a tower to the ground, causing the ground’s potential to rise. The resistance of the soil creates a voltage gradient, which can result in a potential difference between two points on the ground. If a person steps into a ring of this potential difference while their foot is in another, the electricity will pass through their body to make up the difference in voltage.
Touch potential is the voltage difference between an energized object and a person’s body. For example, if an overhead conductor falls on a car and a person touches the car, current could pass from the car through the person to the ground.
Safety measures to follow to reduce the risk of step and/or touch potential:
• Take small, shuffling steps with your feet close together, keeping them in contact with the ground at the same time.
• Continue shuffling until you’re at least 30 feet away from a downed distribution line and 100 feet away from a downed transmission line.
• If any type of wire has fallen on a vehicle or equipment, always considered it energized and do not touch or go near until it is safe to do so.
