On the job experience is extremely Important in helping to make sure you do not overlook all the necessary details that have to be considered to provide an accurate and on time job completion.
One area where it is easy to run into problems is when converting a Computer Room from a Cat5e to a Cat6 installation. Important considerations are the changes necessary in the size of the wire tray or duct support system, for the new cabling.
The average diameter of a UTP Cat5e- 4 pair cable is 0.185 inches and the average diameter of a UTP Cat 6 – 4 pair cable is 0.235 inches. This gives a ratio of 1.27 or about 1/3 added volume, which must be provided for in the cable trays, to put in an equivalent substitute number of Cat6 cables, in a full cable tray, when upgrading the system. If more Cat 6 cables are added in addition, this volume must also be taken into consideration when sizing the cable trays or cable conduit to complete the installation properly.
An example would be using an under floor run of cable tray measuring 2” Deep x 6” Wide. Assuming a 0.185” diameter Cat 5e cable, the cable fill for that size tray is specified at 205 cables. If the tray is filled and all the Cat 5e cables are removed and substituted by Cat 6 cables, only 161 cat 6 cables would fit properly in the installed tray system. Therefore additional cable tray must be installed to accommodate 205 cables, if a full tray is being replaced. This can cause difficult or unsolvable problems to find the under floor useable space to add additional cable tray and supports. These changes have to be solved before starting to install new computer room cabling setup.
Careful inspection of the under tile space available for installation of additional cable tray and supports has to be done during the planning phase of the job to ensure it is possible. Because of piping, power lines, alarm circuitry, etc. under the tiles there may be insufficient room for the additional cable trays or their support hardware. The same considerations apply to over the cabinet or above the ceiling tiles cable ducting, when used to hold Cat 5e cabling which is being changed to Cat6.