Life-cycle cost for Category 5 vs. Category 3

Q: My boss chuckled recently when he read your suggestion about using all Category 5 cable throughout an installation instead of using both Category 3 and Category 5. You stated that there isn`t a large difference in cost between Categories 3 and 5. However, the cost differential--8 cents versus 24 cents--is significant, especially when dealing with 500,000 feet of cable or more.

Q: My boss chuckled recently when he read your suggestion about using all Category 5 cable throughout an installation instead of using both Category 3 and Category 5. You stated that there isn`t a large difference in cost between Categories 3 and 5. However, the cost differential--8 cents versus 24 cents--is significant, especially when dealing with 500,000 feet of cable or more.

His idea was to install one Category 3 and one Category 5 cable to each workstation, and then place a 10% contingency fund of Category 5 cable in the ceiling, ready to drop and route wherever you need an extra cable. This keeps down the cost of the installation and addresses the need for extra cable runs. This procedure seems to work pretty well for us. Any comments?

Jim Slaymon

USA Group

Indianapolis, IN

A: Using all Category 5 cabling was not a suggestion; it was a description of what we are doing at the University of Texas at Austin. In our situation, there is a sound business case for the design. Is this an across-the-board solution? Certainly not.

I speculate that your boss is talking about installation costs, while I was talking about life-cycle costs. When we build a building, it is going to be there for a while, and so should the cabling. With the number of active network connections on campus surpassing the number of telephone lines and continuing to spiral upward, we are clearly justified in installing a 100-megahertz cabling infrastructure that will also support voice. If you are installing separate voice and data cabling systems, your design may be different.

We also purchase cable in large quantities and on a regular basis. Our bids from cable vendors run fairly consistently 8 to 10 cents per foot higher for Category 5 cable. But that is easily recovered in reduced cable administration cost, both in cable recordkeeping and in the speed and ease with which adds, moves, and changes can be made over the lifetime of the cabling.

Donna Ballast is a communications analyst at the University of Texas

at Austin and a bicsi registered communications distribution designer (rcdd). Questions can be sent to her at Cabling Installation & Maintenance or at PO Drawer 7580, University of Texas, Austin, TX 78713; tel: (512) 471-0112, fax: (512) 471-8883, e-mail: ballast@utexas.edu.

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