Underground Distribution

Overhead lines aren't the only way of bringing power to homes. Neighborhoods that seem to be free of electric wires and poles have underground power lines.

When low-voltage lines are underground but transformers and medium-voltage lines are overhead, this is called a hybrid overhead/underground distribution system. When the system is entirely underground, the medium-voltage lines are also buried, while transformers are mounted on ground-level pads or in underground vaults. The latter system is more common in densely populated areas and in certain housing developments.

Power line undergrounding is gaining popularity. In the United States, most new residential developments have an underground distribution network. In Québec, wirefree environments are becoming a feature of the urban landscape. More and more towns and cities are choosing to bury distribution lines in new neighborhoods.

In addition to improving the landscape, undergrounding protects electrical equipment from bad weather and vegetation. It also helps create more open space in neighborhoods. In Québec, about 11% of the distribution lines are below ground. This figure is consistent with undergrounding rates elsewhere in Canada. Undergrounding any distribution system is more expensive than building overhead lines, and the decision is up to provincial and municipal authorities, not utilities.