Overhead DISTRIBUTION lines consist of wires that are supported on utility poles about 10 metres (30 feet) high. These poles are most often made of wood, but are sometimes concrete.
The wires at the top of the poles are medium-voltage conductors, which carry 750 to 34,500 volts. These bare metal wires are not insulated.
DANGER! Never let yourself or anything else (a tool, scaffolding, construction materials or a tree branch) come within three metres of a medium-voltage wire when pruning or felling a tree.
TRANSMISSION lines are much larger than distribution lines. Their support structures come in a variety of shapes and heights. They can be made of metal latticework, concrete or wood, but the wooden structures are taller than distribution line poles.
Transmission lines are generally located in cleared corridors called rights-of-way.
Transmission lines carry from 44,000 to over 735,000 volts.
DANGER! These high-voltage lines are not insulated, and nothing should come near them. Carrying out work near these lines or planting anything in the right-of-way without proper authorization is prohibited.