We’ve already gone over the proper management of high voltage sites on a big-picture level, from general safe practices, respecting the right-of-way, possible shock hazards, and underground pipe and irrigation systems management. This time, we’ll go over structures, vehicles, and natural and man-made disasters.
1. Structural safety precautions
For obvious reasons, fences should never be in the right-of-way, if possible. This applies to all barbed wire and woven fences, which may assume an induced voltage near power lines. If, for whatever reason, you wish to construct a fence in the right-of-way, you must contact the appropriate local authority. The fence must be grounded at each end and every 200 feet with a metal post driven at least 2 feet into the ground. The fence must also be a minimum of 50 feet from all structures.
In the case of electric fences, which cannot be grounded, a filter can be installed that removes induced voltage from power lines.
Buildings may collect an induced voltage even outside the right-of-way. This voltage typically drains harmlessly through the plumbing or metal frame. But, if it doesn’t, it can result in nuisance shock. To avoid this, buildings within 100 feet of the outside wire of a power line, more than 2,000 square feet of metal surface area, or with stored flammable material up to 250 feet from the outside wire must have grounded metallic components.
Temporary or permanent structures within the right-of-way, including light standards, signs, utilities, etc. can be unsafe. Permissible heights vary based on proximity to power lines, composition, and other variable conditions.
Swimming pools are not allowed within rights-of-way.
2. Vehicular safety precautions
Vehicles are tricky. They can collect voltage in some circumstances — like when a truck is parked on a nonconductive surface of rock or asphalt. This can lead to nuisance shock or more serious consequences.
To avoid induced voltage in your vehicle, always park on a conductive surface. If, for whatever reason, you must park or operate on a nonconductive surface, temporarily ground your vehicle by attaching a chain or leaning a metal bar against the side. Also, it goes without saying that on-site refueling near a power line is prohibited.
Operational vehicles must take special precautions when working near power lines. No metal objects should be raised more than 14 feet into the air beneath a power line, as the distance between power lines and the ground has already been calculated for minimum safety.
Boats passing beneath power lines that stretch over bodies of water should first check their clearance. All masts and guy wires should be electrically connected to underwater metallic components, like the keel or centerboard.
3. Natural disasters
Lightning strikes are a very real threat. Lightning always strikes the highest nearby object, which will typically be a power line or tower on any power
generation site. Transmission facilities themselves are lightning resistant, but that doesn’t mean that you should be anywhere near a power line or
tall object during a storm. Lightning is still dangerous even if you are standing on the ground near a tall, grounded structure.
Fires are a serious safety hazard — especially near power lines. Smoke or hot gas can make the air electrically conductive, making power lines incredibly dangerous if there’s a nearby fire. This is why burning is absolutely forbidden in the right-of-way, and can lead to massive power outages.
4. People precautions
We went over tower safety precautions in Part 1 of this series, but it doesn’t hurt to review the guidelines. Never climb towers, shoot or damage transmission facilities, touch fallen wires, or attach anything to the tower itself.
Trespassing and Vandalism
For whatever reason, transmission sites have always had their fair share of curious explorers. Vandalism happens. So does trespassing. But less obviously dangerous are supposedly “harmless” actions like dumping waste or hunting on land nearby. Whatever the case, anyone without certification or approval to work at a transmission site should not be there. Often a reward of up to $25,000 is available for information leading to the arrest of culprits.
Kite Flying / Model Airplanes
Recreational flying, kite flying, and model airplane-flying are all strongly discouraged. Recreational flyers in planes should fly well over power lines, and people on the ground should do their kite flying elsewhere. Since winds are largely unpredictable, the chances of accidents increase.
The local power authority usually owns any and all trees near a right-of-way, so you wouldn’t be in a position to log a tree anyway. But if you somehow were (let’s say you were contracted), it goes without saying that logged trees must fall away from power lines. Trees are electrically conductive, and if a tree falls anywhere near a power line (or in the worst case scenario, on one), you should leave it alone, clear the area, and contact the authorities immediately.