|  | 8.9 | Design Practice No. 2: Multiple Earth Ground Problems
| 8.9.3 | Company A: backbone media
This will be a new installation; therefore, the networking media for the horizontal cabling will be CAT 5 UTP. Now you must determine which types of networking media you should use for the backbone cabling. After a preliminary study, you have narrowed the choices to two types - CAT 5 UTP and 62.6/125 µ fiber-optic cable. Because of the high cost of installation, you would like to avoid using fiber-optic cable unless absolutely necessary. However, based on your preliminary study and projections, you have determined that it may not be necessary to use fiber-optic cable because UTP could sufficiently carry all anticipated network data for the next ten years. There are, however, two more factors that could influence your decision - safety and distance. In light of this, you must consider the following points: The building has three different earth grounds. Could this present any safety problems for company A's network? The maximum distance specified by TIA/EIA-568-A for CAT 5 cable is 100 m. Because the height of each floor is 4.9 m, you will need to exceed this distance if you use this for the backbone cabling. Can you think of a way to solve the problem of distance between the POP and the MDF? Can you think of a way to solve the problem of distance between the MDF and the IDFs? The repeating hubs will be located in IDFs.
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