Best Practices for Copper Installation

Written by Julianus Yu

We used our own installations of copper cabling, as well as the tips and techniques of many others, to create guidelines for you to follow to ensure that your UTP cabling system will support all the applications you intend it to. These guidelines include the following:

Following standards

One of the most important elements to planning and deploying a new telecommunications infrastructure is to make sure you are following a Standard. In the United States, this Standard is the ANSI/TIA/EIA-568-B Commercial Building Telecommunications Cabling Standard. Standards development usually lags behind what is available on the market, as manufacturers try to advance their technology to gain market share. Getting the latest innovations incorporated into a standard is difficult because these technologies are often not tested and deployed widely enough for the standards committees to feel comfortable approving them.

Making sure you do not exceed distance limits

One of the most important things that the ANSI/TIA/EIA-568-B Standard defines is the maximum distance that a horizontal cable should traverse. The maximum distance between the patch panel (or cross-connect, in the case of voice) and the wall plate (the horizontal portion of the cable) must not exceed 90 meters (285 feet). Further, the patch cord used in the telecommunications closet (patch panel to hub or cross-connect) cannot exceed 5 meters (16 feet), and the patch cord used on the workstation side must not exceed 5 meters (16 feet).

Some tips relating to distance and the installation of copper cabling include:

• Never exceed the 90-meter maximum distance for horizontal cables.
• Horizontal cable rarely goes in a straight line from the patch panel to the wall plate. Don’t forget to account for the fact that horizontal cable may be routed up through walls, around corners, and through conduit. If your horizontal cable run is 90 meters as the crow flies, it’s too long.
• Account for any additional cable distance that may be required as a result of trays, hooks, and cable management.
• Leave some slack in the ceiling above the wiring rack in case retermination is required or the patch panel must be moved; cabling professionals call this a service loop. Some professional cable installers leave as much as an extra 10 feet in the ceiling bundled together or looped around a hook.

Good installation techniques

When you start installing copper cabling, much can go wrong. Even if you have adequately planned your installation, situations can still arise that will cause you problems either immediately or in the long term. Here are some tips to keep in mind for installing copper cabling:

• Do not untwist the twisted pairs at the cable connector or anywhere along the cable length any more than necessary (less than 0.5 inches for Category 5 and 5e, less than 0.375 inches for Category 6).
• Taps (bridged taps) are not allowed.
• Use connectors, patch panels, and wall plates that are compatible with the cable.
• When tie-wrapping cables, do not overtighten cable bundles.
• Staples are not recommended for fastening cables to supports. If they are used, don’t staple the cables too tightly. Use a staple gun and staples (plastic staples, if possible) that are designed to be used with data cables. Do not use a generic staple gun; you will be on the express train to cable damage.
• Never splice a data cable if it has a problem at some point through its length; run a new cable instead.
• When terminating, remove as little of the cable’s jacket as possible, preferably less than three inches. When finally terminated, the jacket should be as close as possible to where the conductors are punched down.
• Don’t lay data cables directly across ceiling tiles or grids. Use a cable tray, J hook, horizontal ladder, or other method to support the cables. Avoid any sort of cable-suspension device that appears as if it will crush the cables.
• Follow proper grounding procedures for all equipment to reduce the likelihood of electrical shock and reduce the effects of EMI.
• All voice runs should be home-run, not daisy-chained. When wiring jacks for home or small office telephone use, the great temptation is to daisy-chain cables together from one jack to the next. Don’t do it. For one thing, it won’t work with modern PBX systems. For another, each connection along the way causes attenuation and crosstalk, which can degrade the signal even at voice frequencies.
• If you have a cable with damaged pairs, replace it. You will be glad you did. Don’t use another unused pair from the same cable because other pairs may be damaged to the point where they only cause intermittent problems, which are difficult to solve. Substituting pairs also prevents any future upgrades that require the use of all four pairs in the cable.