There can be several ways to accomplish MAC work. For work in an existing structure, MACs can be as easy as installing another patchcord between the patch panel and the appropriate resource in the telecom room (TR), then plugging that cord into the new device in the work area or office area (the new PC, printer, phone, etc.). If new cabling is required, an electrical contractor should get involved. Adding new cables to an existing live network provides challenges not experienced in a new installation, where rough-in, trim out, testing and documentation occurs before the owner is on-site.
Glenn Sexton of Northwest Information Services Inc., Portland, Ore., is a member of TIA, the American Institute of Architects (AIA) and NFPA’s Architects, Engineers and Building Officials Section (see www.nispdx.com). Sexton said a company’s warranty should be a major consideration involved with MAC work.
“When doing any MAC work, there is the consideration of the effect of that work on an organization’s warranty. The building owner may have an extended warranty that covers existing installations for this type of work. The warranties typically cover the product for between 15 and 25 years, but the caveat is that the installation must be completed by a certified contractor. The certification could be a simple registration, but more likely, it requires product-specific training. Some warranties can be voided if MACs are performed by noncertified contractors,” Sexton said. This could be a major issue and should be clarified before actual work commences.
Many factors should be considered when adding new cabling, including looking at already installed/ existing products and the owner’s expectations for the newly installed products’ ability to work with the existing products (interoperability). The existing conduit must be able to handle the possibility of more cable(s), and the box must be large enough to accommodate additional jacks. The means of access—dropped ceiling, cable tray, access floor or hard conduit—should be taken into consideration along with the possible necessity of new faceplates.
It is important to be familiar with pathway availability and the capacity of sleeves already in place. Also, be sure to take note of firewalls and the type of firestopping in place. It is critical to either match the existing firestop or replace it entirely, because different chemical compositions may not mix, and in fact, they could nullify the firestopping properties of the product.
Know whether there is a need to use the existing patch panels and if not, whether rack space is available to add panels. Be familiar with testing and certification requirements and what the owner expects for labeling and documentation.
Contractors should also be aware of scheduling and environmental factors. Be sure to learn if the work will be done during regular work hours. Be aware of whether other work, such as adding new electrical outlets, will be done at the same time. Take note of the availability of spare ceiling tiles in the event of breakage. Furthermore, all ceiling tile work should be done wearing white cotton gloves to protect the tiles from dirt and body oils that can stain them. Familiarize yourself with the added functions of security, alarm and access control. Finally, there may be heating, ventilating and air conditioning impacts with raised floors.
The industry now demands more of contractors who do MAC work. New proficiency requirements relate to the handling of necessary components.
For instance, unshielded twisted pair (UTP) cable is a very robust product, but it has to be installed according to the manufacturer’s instructions. Pulling tension of the cable is limited to 25 pounds of force, which differs from the pulling force for No. 10 AWG. UTP usually will not tolerate a bend radius of less than 4 times its diameter under load without suffering some damage that will result in poor test results. Since most UTP falls between .25 and .35 inches in diameter, that allows a 1- to 1.4-inch bend. Cable dollies and pulling rollers or pulleys almost always are required.
Another area of proficiency requires contractors to be properly trained in the use of the insulation displacement connector (IDC) tools for termination of today’s technology. Some manufacturers have developed their own proprietary tool that expedites the installation of their product(s), while providing exacting conformity with repetitive terminations. It is strongly recommended that installation and MAC work be performed by individuals who are trained in the proper termination techniques for the product(s) being used.
All the contractor’s work needs to be tested to the level of its rated performance. This means a contractor must have the current generation of recently calibrated and certified testing equipment and that they have their technicians properly trained to use that equipment. Training includes interpretation of results in case troubleshooting is required.
The job must be fully documented with labels fixed to the cables, faceplates and patch panels. It is important that labels are machine-produced, with permanent identification affixed to the cable as well as the faceplates and patch panels. Such labeling requires special equipment and proper training in its use.
One way to offset some of these requirements is to use a cabling installation system (CIS). This puts all the installation processes and aids into one system, and it allows for pulling the cable off the reel(s) all the way up to ceiling pathways and its final termination. A CIS pulls, labels, reduces twisting and friction and helps maintain the alien near-end cross talk (ANEXT) performance of the future high-speed cables.
For a customer using Voice over Internet Protocol (VoIP), the installer must be able to test and certify Power over Ethernet (PoE) installations, which is the current trend in voice communications. Unlike the traditional private branch exchange (PBX) voice systems, VoIP requires power to be introduced at the Ethernet switch, into the cable span (mid-span) or at the device itself. The current PoE standard is IEEE 802.3af that provides 48V DC over two pairs. The drivers for PoE are VoIP applications, wireless access points (WAP) and security cameras. Installers/technicians must be able to test and certify PoE installation.
How it all began
Remember, we have had it easy in the past. The cabling that supported traditional voice systems was unshielded twisted pair (UTP) cable, but it was anywhere from four to 25 pairs using 24 gauge wire. Data cabling often was coaxial, and sometimes UTP, but nearly always proprietary. Since the industry first set 100 meters as the transmission distance—for the horizontal from the telecom room out to the work area—cabling, we’ve moved from Category 3 cabling that handled 10 Mbps Ethernet transmission to Category 6 that handles 1,000 Mbps Ethernet and are moving to tomorrow’s Category 6A that will handle 10 Gbps Ethernet. It also is possible for the Category 6 cabling to handle 10 Gbps for less than 100 meters. Category 8 UTP copper cable is being produced today, while Category 7 already exists. Currently, UTP is the standard for communications cable.
In the 1990s, it was not uncommon to install two different cables, i.e., one for voice (typically a Category 3) and one for data (Category 4 or 5). This practice was supported by the fact that the telephone system cable typically was terminated on 66 or 110 blocks mounted on a plywood backboard in the telephone room, and the data was terminated in a computer room on modular patch panels.
Then, a slow and steady transition occurred—the two systems came closer, and more often than not, they were located in the same room. A universal “structured” cable approach replaced the two different systems. Universal jacks at the work area were connected via UTP to a universal patch panel containing jacks in 24-, 48- or 96-port configurations. The patch panels then were connected to the proper resource, voice or data, using preassembled modular cords. The blending of the two also has brought forth the terms “telecom cabling” and “communications cabling,” which are used interchangeably by most in the industry.
Today, UTP typically is specified at construction with 2, 3 or 4 individual cables to be placed to each work area. Electricians install the boxes, conduit and pathways for communications as a part of Division 16 rough-in. Communications cabling is specified in Division 17, or more correctly, the new Division 27. Communications cabling has been treated as a specialty and often is installed by a separate division of an electrical contractor. Many states have a different classifications for “limited energy,” with some requiring a supervising journeyman to oversee the installation of the communications cabling.
Getting involved in MAC work can bring large payoffs, but this payoff comes with some preparation. For starters, scope out the functions in a customer’s company that affect datacom maintenance work. Do this on any existing or new job, during a walkthrough prior to the contracted work or later when you are on the job. Next, include any of the customer’s data/telecom conditions that could affect your work into your work plan. Also, review what maintenance-related tasks you want and need to become proficient in and get that expertise.
Knowing the condition of any part of a customer’s environment that may affect maintenance work you can do, plus being proficient in today’s technologies, will put you ahead of others who are less concerned with this type of information. You can make this information work for you. EC
MICHELSON, president of Jackson, Calif.-based Business Communication Services and publisher of the BCS Reports, is an expert in TIA/EIA performance standards. Contact her at www.bcsreports.com or firstname.lastname@example.org.