A cable tray is a rigid cover—usually in the form of an open or closed channel—designed for guiding and protecting electrical, signal, telecommunication cables, or installation pipes. It can be made from plastic, metal, or specialized materials such as halogen-free technopolymers. Types of Cable. Cable ducts are usually made of plastic, PVC, or aluminum. They are lighter and good for simple jobs. 2 How far apart should the metal supports be? 7. 3 Are stainless steel ties better than plastic ones? The. Two fundamental components in achieving this are cable trays and cable ducts. They enable safe and orderly cable routing in various environments—from residential buildings, through industrial facilities, to IT and transportation infrastructure.