Lightning conductor, diagram. A lightning conductor (or lightning rod) protects tall or isolated buildings from lightning strikes by providing an easier path for the current to flow to earth than through the building. The conductor consists of a metal strip, usually copper, of very low resistance connected to the ground below. Negative charge builds up at the base of storm clouds, inducing positive charge in the objects below. If charge builds up enough it will discharge in the form of a lightning strike. The lightning conductor provides the easiest route and carries the charge safely into the Earth without damage to the building.