Accirding to the vast majority of the studies, the short answer is "No". A small number of studies show some indications of relationship. It is extremely difficult in science reports to say that you are sure 100% (not 99,99%) that "something" DOES NOT cause "something other".
Only if you touch them :) Some believe the electro-magnetic energy from power lines may cause cancer. Most are concerned with overhead power lines when needed to trim trees, or access other elevated areas.
20 feet.
Overhead power lines are insulated from ground, typically using strings of glass or ceramic insulators. The wire itself is bare, though - it does not have insulation on it. There are many different types of overhead power line, but I'm not aware of any that actually have insulation.
Freezing rain and heavy snow cause power failures by building up on overhead power lines, overburdening them. They either snap the line from the weight or come loose from their connectors to the poles and come down.
This can vary on the power lines and trees. Typically it would not be the snow, but the ice, which would cause problems, though. Icicles forming on overhead power lines, weighing them down, or icicles on tree branches, causing them to bend or break and fall into the power lines, would be the most common problems in winter weather, rather than a certain amount of snowfall.
It is safer living by buried power lines because they won't fall on your house or car in heavy winds or ice storms.
Overhead obstacles - such as power-lines or bridges.
to reduce current and the resulting I2R waste of power.
No.
Power lines have been known to cause anxiety in horses and prevent adequate sleep.
powerlines mounted on pylons, see Overhead power line. For lines carrying information, see Overhead cable. An overhead line or overhead wire is used to transmit electrical energy to trains, trolleybuses
William T. Taylor has written: 'Overhead electric power transmission engineering' -- subject(s): Overhead electric lines 'Practical water-power engineering' -- subject(s): Hydraulic engineering, Water-power