Close encounters: the phenomenon of induction

A utility provider was undertaking a major project that involved upgrading the voltage of existing power lines in a rural area from 250Kv to 500Kv, when technicians encountered fuel containers being stored dangerously close to the power lines. The landowner wasn’t aware of the existing danger, or why the location of his fuel containers would become even more hazardous with the imminent voltage increase. This farmer was certainly not alone.

Many people are unfamiliar with the phenomenon of induction—where power lines may cause nearby structures such as buildings, sheds, storage bins, railroad tracks, fences and even heavy equipment or machinery to become energized over time.

Sharing of rights of way by private landowners and power line utilities is common, given the vast network of power lines and towers that span all over our province. Utilities retain an important right-of-way agreement governing activities that might impact public safety or interfere with the operation of power lines on privately held lands. Sharing the rights of way with power utilities isn’t usually problematic, but it can create unique hazards due to induction—hazards that may be particularly prevalent on the farm.

Farmers often choose to store fuel bins or equipment near the edge of their property, where power lines are frequently located. Depending on the voltage of the line and the proximity and characteristics of the equipment or structures in question, induction can create hazards of electric shock, arcing and even fire or explosions. Many farmers, even those who are familiar with—and abide by—the “7 Metres Safe” rule when operating equipment near power lines, may not realize the inherent dangers of induced voltage over time. Operators who have parked equipment near a power line for even a short time may have experienced a “shock” upon returning to their vehicle. Imagine how that same effect can multiply and potentially become dangerous over a longer period of time in close proximity to high-voltage power lines.

The safe distance between buildings and structures and transmission lines depends on the voltage of the line, the type of construction, building type and height and location. If you want to erect or relocate a building contact your local utility to be advised of the safe distance requirements. Your utility can also help you “ground” any building that could store an electrical charge. There are many ways to turn a potentially dangerous situation into a safe one. If you’re in doubt, the best thing to do is contact your local electric utility for advice and assistance.