Tree trimming often requires working at a great height, and this may mean working near power lines. Electrical lines present a real hazard to anyone attempting to trim a tree. Touching a live wire can cause a life threatening shock, and if a line is accidentally cut during the process of trimming, it can endanger your life. It is integral that certain safety procedures are heeded when attempting to trim a tree around power lines.
Call your energy company to de-energize power lines to ensure your safety. The Canadian Centre for Occupational Health and Safety recommends you assume all power lines are energized whether or not the power company has de-energized the lines.
Mark off the area underneath the tree using caution tape to indicate that someone is working above, and to keep people away from the bottom of the tree.
Keep a minimum of 10 feet away from power lines, as recommended by the American Occupational Safety and Health Administration (OSHA). Use a professional tree trimming service if the tree is closer to the power lines than the minimum requirement.
Attach your ladder to a secure limb of the tree using rope to prevent falling and to ground the ladder, which helps draw electricity away from you in case of an accident.
Cut branches using plastic handled pruning shears, loppers or a hand saw. Make an initial cut to large branches on the bottom of the branch, 6 inches away from the the shoulder where the branch comes out of the trunk. Cut a third of the way through the branch. Cut again on the the top of the branch until the branch safely falls away. This helps control the descent of the branch and prevents branches from coming tangled in power lines. Remove the stump of the branch up to the shoulder.
Cut small branches just below the first bud of the branch using pruning shears.