Should You Use or Replace Old Wiring?

Imagine that you show an office tenant a prospective space that is fully wired to the patch panel. Or you show a tenant a space that is wired to the patch panel but all lines are cut at the base. In either case, should the wiring be replaced? The answer is: Maybe, maybe not.

I have spoken to a number of wiring installers, movers, and computer experts about this subject and have never received a straight answer to this question. The cost to the tenant to rewire a space can run to $100 to $150 a drop; the cost to reuse wiring may or may not be cheaper in the front end, but could cause enormous problems once the tenant moves in.

Some installers will tell you that if the space is fully wired to the patch panel and each potential workstation or office is clearly marked, the wiring can be reused. Others will suggest that wiring can be damaged over time from being stepped on, run over with chairs, and the like. And, over time, communication through the wire may cause erratic signals that disturb work or cause the connection to be lost. If the integrity of your network is worth more than the price of new patch cables, then I suggest that you use brand new cables for all closet cleanups and network moves.

Some installers will tell you that, when wires have been cut, it costs more to test the wires to find out where they should end up than to simply rewire the office. Others will tell you that testing the lines is not expensive and far cheaper than rewiring.

Here are the basic considerations if you are faced with this issue:

1. What type of wiring are you looking at? Cat 3 or Cat 5A wiring is considered outdated. The standard wiring today is Cat 5E, with some advanced installations including Cat 6 and the recent addition Cat 7. If you do not have at least Cat 5A and you are planning on leasing the space for at least three years, you are better off rewiring.
2. Does the cable appear to be crimped, sharply bent, or damaged in any way? If so, it is better to rewire than to take the chance of installing you’re computer system to potentially faulty wiring.
3. Does the existing installation or the new installation cables have plenty of slack and are neatly coiled up in the ceiling or nearest concealed place? It is recommended that you leave at least 5 feet of cable at the work outlet side and 10 feet at the patch panel (wiring hub side). Tight lines could easily get crimped in the ceiling, causing faulty signals through the lines.
4. Is every termination point labeled? Use a unique number for each segment. This makes moves, additions, changes, and troubleshooting as simple as possible. If the client is planning on reusing old wiring, ask if it is properly numbered. If it is not, the client should test each line to determine its final access point.

The most important advice to give a client is to seek counsel from several professional wire contractors before making a decision. More important, given the issues above, do not make the mistake of saying, “Oh yes, the place is fully wired and ready to go.” You could be drastically wrong.