Line wires must be so placed that moisture cannot form a cross connection between them; must not be less than twelve inches (12") apart except when in conduit or multiple conductor cable; must not be in contact with any substance other than their insulating supports; must be at least eight feet (8') above the highest point of roofs over which they pass, or to which they are attached; all roof structures must be substantially constructed. Wherever feasible, wires crossing buildings should be supported on poles independent of the building. (Prior code § 8-4-10)