Electrical burn. Close-up of an electrical burn on fingers. Electrical burns such as this one, although seemingly small, may have devastating effects due to the action of electricity on the heart. Burns are classified according to the damage they do. Sunburn, and other reddenings of the skin, are called first degree burns. If there is blistering and deeper skin damage, they are second degree burns. Third degree burns destroy the entire skin thickness, as seen here, and may expose muscle and bone. Burns such as this almost always cause scarring, and skin grafts are performed if the burn is extensive.