Every year, the ground settles and expands with changing weather conditions and temperatures — but did you know that these changes affect both the height of overhead power lines and the depth of underground lines?

Overhead Power Lines

While most power lines are more than 4 metres above the ground, sagging lines are a common hazard that often go unnoticed.

The tension of the wire between the poles determine how much power lines will sag. Temperature, ice, snow and softening of surrounding earth can all put pressure on the wire, power poles and other infrastructure, leading to sagging lines.

If you notice sagging power lines in your area, contact your local utility company so that they can adjust the height of the line and always keep your equipment at least 7 metres away from overhead lines.

Underground Power Lines

While underground utilities are usually buried safely below, freezing conditions in the fall and winter followed by the spring melt can impact the grading of soil. As a result, the soil can compact and cause power lines to migrate to shallower ground.

When power lines exist only a few centimetres below the surface, the risk of contact is at an all-time high. Before breaking ground, always locate underground utilities and follow safe practices for exposing buried lines.

Find more information on the safe excavation requirements in Alberta in these sections of the Alberta Occupational Health and Safety Code, Part 32 Excavating and Tunnelling:

1. Disturbing the ground (Section 441)
2. Locating buried facilities (Section 447)
3. Exposing buried facilities (Section 448)

Consult the Alberta Electrical and Communication Utility Code for excavation work in the vicinity of underground power lines (Section 2-020).