Often trees mature that homeowners want removed or cut back from facilities. Trees that can come in contact with the energized power line, bare wire, or insulated wire can be a serious hazard.
NEVER attempt to do any tree work on a tree that could contact the power lines or other electrical equipment. Trees can have decay or rot that you may not notice and when you start cutting it you will lose control of the fall direction. Hire or seek the advice of professional tree experts, ISA certified Arborists, before you attempt to work on trees that may hit the power lines.
If you are concerned about a tree that may contact the power line, contact your utility immediately.