Underground Cables


The electric utility industry has been utilizing direct burial power cables for rural or residential electrical distribution. Underground power cables typically consist of a conductive core of a bundle of conducting strands, surrounded by a semi-conducting shield layer, an insulation layer, a second semi-conducting shield layer, a layer of metallic tape or helical concentric neutral conducting strands, and a polymeric jacket or sheath. The conductor may be stranded from multiple wires, or less commonly a solid conductor core may be utilized.

Fiber optic cables have become a preferred transmission system for telecommunication and data communication. Fiber optic cable is composed of a bundle of long, thin fibers of glass, plastic or other transparent material closed with a protective sheath. The advantage for fiber optic cable over conventional cable lies in its transmission characteristics. Because of the fiber's thinness and superior attenuation characteristics, a fiber optic cable can carry a much higher rate of information over many more channels than a comparably sized wire cable. Fiber optic cables are generally installed underground inside a conduit. The conduit is often laid in trenches and can extend a mile or more. The conduit generally has a smooth inside diameter throughout its length. Several methods exist for installing the fiber optic cable into the conduit.