| Fiber optic cables are exposed to electrical, | | | | A cable tray is an assembly of units made of metal or |
| mechanical, chemical and environmental elements, so | | | | other noncombustible materials that form a continuous, |
| proper installation is critical for the long-term stability | | | | rigid support for fiber cables. Cable trays are used |
| and survival of fiber cables. | | | | throughout the industry and they greatly simplify the |
| Cable installation must also meet the NEC(National | | | | installation of fiber optic cables. |
| Electric Code) and local building codes. NEC indicates | | | | Cable trays come in several different types including |
| that fiber optic cables can be placed in the same | | | | ladder type, trough type, channel type and solid-bottom |
| raceway, cable tray or enclosure with CATV, | | | | type. |
| telephone, communication circuits and Class 2 and 3 | | | | Ladder type cable tray is a metal structure consisting |
| remote control signaling circuits. | | | | of two longitudinal side rails connected by individual |
| Note that you should never put the fiber optic cable in | | | | transverse members. The transverse members |
| the same enclosure that houses electrical terminations. | | | | provide the support for fiber cables. |
| What are conduits? | | | | Trough type cable tray is also a metal structure. It |
| Conduit is a tube or trough for protecting electrical or | | | | consists of a ventilated bottom and has closely |
| communication wires and cables. It may be a solid or | | | | spaced supports within integral or separate longitudinal |
| flexible tube in which cables are run. They house and | | | | side rails. |
| protect the fiber optic cables as well as any other | | | | Channel type cable tray consists of a one-piece |
| type of data or communication transmission line. | | | | ventilated or solid-bottom channel section. |
| Underground conduits are also called ducts and consist | | | | Solid-bottom type cable tray is a metal structure that |
| of one or more conduits spaced closely together. | | | | has no openings in the bottom. Integral or separate |
| They are often buried directly in the ground in concrete | | | | longitudinal side rails provide the support for the fiber |
| casing. Duct lines terminate in underground vaults called | | | | cables. |
| manholes. Conduits are made of fiber, PVC, PE and | | | | What are pull boxes? |
| other materials. | | | | Pull boxes are used to break up long conduit lengths |
| Above ground conduits are made of metal or | | | | for easier and lower tension cable pulls. |
| nonmetal materials. They can be used in exposed or | | | | Pull boxes are usually placed near conduit bends and in |
| concealed locations aboveground. | | | | long straight runs. You should use at least one pull box |
| Characteristics of a good conduit installation | | | | after every second 90° bend and in long conduit |
| 1.Good mechanical properties to withstand the forces | | | | spans. |
| imposed by cable installations | | | | When pulling cable out of pull boxes, ensure that the |
| 2.Observes fiber optic cables minimum bending radius | | | | cable's minimum bend radius is always observed. |
| 3.No sharp edges or bends touches the fiber optic | | | | Cable pulled through a corner pull box should first be |
| cables throughout the route | | | | pulled into a loop since the sharp corner of the pull box |
| 4.Meets current and future expansion requirements | | | | can easily damage the cable and the fibers. |
| What are cable trays? | | | | |