Open wire, synonymous with overhead line, is a bare conductor not surrounded by insulation and supported separately above ground on insulators.
Open wire refers to a bare conductor that is not enclosed in insulation and is held aloft on separate supports above ground, the same arrangement known as an overhead line. Air serves as the insulation between conductors, which are kept apart by spacing and mounted on insulators attached to poles or other structures. This is one of the oldest methods of carrying electrical power and communication signals.
Because the conductors are bare and rely on air and spacing for separation, open wire construction requires that conductors be kept apart and clear of other objects. The approach has been widely used for power distribution and early telephone and telegraph lines, where long spans of bare conductor were supported across the landscape.
In commercial and industrial contexts, understanding open wire helps in distinguishing it from insulated cable and in recognizing the role of conductor spacing and support in overhead systems. The principles of separation and support contrast with the self-contained insulation of modern cable.
Because the bare conductors depend on air and spacing rather than insulation, open wire construction requires careful separation and clearance, a contrast with modern cable that consolidates insulation, shielding, and protection into a single self-contained product.
At Windy City Wire, the focus on insulated low-voltage cable contrasts with open wire construction, illustrating the value of integrated insulation and shielding. Understanding both approaches helps customers appreciate how modern cable consolidates protection and signal performance into a single product.
Also called overhead line