Copper cables remain a key element in most structured wiring systems, even as the amount of fiber optic cable in structured wiring networks continues to increase.
No one questions the importance of correctly making every cable connection in alarm, surveillance and building control systems. One faulty connection can bring down a whole network. Of course, the first step in making a good termination is properly preparing the wire for the type of connector being used.
Representatives of three manufacturers discuss terminating copper voice/data/video cabling and the importance of preparing the wire to be connected.
Dave Mueller, Klein Tools’ senior product manager, voice/data/video, said: “VDV tools are made especially for low-voltage work via coax, utility or twisted-pair cable. These tools include cutters, strippers, crimpers, punchdown tools, connectors and testers. Cutters and strippers are the basic ‘prep’ tools.
“Using tools made specifically for VDV increases efficiencies. By using the correct tools, connections are made more accurately, productivity increases and installations are safer. In the long run, the right tool saves an installer both time and money.
“To prepare wires for RJ-45 modular plug connections, about 2 inches of the data cable outer jacket material should be removed, exposing the four pairs of colored twisted wires. Individual pairs of wires need to be untwisted, straightened and then arranged in a specific color pattern per the desired standard. Straightened, arranged wires are then trimmed to a half-inch length for insertion into the modular connector. Generally a ‘data cable’ stripper is used, a plastic ring-handled or clothes-pin-style tool with one blade to score the jacket material. The tension on the handles must be adjusted not to cut through the jacket material. One common mistake when preparing twisted-pair or data cable is applying too much pressure when stripping and then cutting through the outer jacket material. Proper procedure is to simply ‘score’ the outer jacket, bend at the score and ‘snap away’ the stripped piece of material. This leaves the inner wires untouched.
“Another mistake is improper arrangement of the eight wires. Modular plugs have a positive and negative polarity associated with the gold contacts. If both ends of the cable aren’t arranged in an identical order, then the connection will fail.
“For coax compression connections, the coax cable end needs to have the outer jacket, wire braiding, foil shield and inner dielectric insulation all stripped to a specific length. Generally, the preparation is a two-level strip. Level 1 is stripping all material away from the copper center conductor at least a quarter of an inch or 6.3 millimeters at the end of the cable. Level 2 strips the jacket material back an additional quarter-inch, leaving the wire braid, foil shield and white dielectric exposed in this section,” Mueller said.
Jeff Meader, Ideal Industries’ business unit manager, said: “A properly installed and well-documented cabling network is a major point of pride for most veteran installers. They know that the overall success and profitability for each project will depend critically upon installers getting it right the first time, quickly and efficiently. They also know that the certification crews generally keep tabs on which installers provide them with the best results. Installers who have the right tools and know how to use them are in a much better position to deliver on all counts.
“The reasons for failures today are primarily due to issues at the point of installation. Almost all cable manufacturers have refined their processes to approach or achieve Six-Sigma-quality levels. Therefore, installers can generally have a high level of confidence in the integrity of their raw bulk cable. The vast majority of failures are introduced through the process of pulling, cutting and terminating the physical lengths of cabling to form specific network configurations.
“The most commonly used coaxial connectors in CATV, satellite and video applications are called ‘F’ connectors. F connectors are available in compression, crimp, push-on, and twist-on styles. For security applications, BNC-style connectors are typically used. The major advantage in using compression connectors is that they provide for permanent watertight connections. An alternative to compression technology for coax is the push-on connector. It is pushed onto the cable until the white dielectric is even or flush with the small opening. The push-on connector is a permanent termination and cannot be pulled off. No crimp or compression tool is required.
“To cut coax cable, use snips that have an oval-shaped cutting aperture in order to apply cutting pressure around the whole cable and to avoid pressing the coax down into a flat cut. Use a stripping tool specifically designed for coax and that can handle a variety of different cable diameters. When using a new type stripper, strip the coax by inserting it into the tool and rotating the stripper several times around the cable. There are also mechanical tools that speed up the process with a spring-action operation that grips and strips all in one motion.
“Terminating RJ-45 requires that twisted-pair wires be separated into the proper sequence, either EIA/TIA 568 A or B. Flatten the pairs so they are close together and in the right color sequence. Then trim them to a half-inch from the outer jacketing and slip the plug onto the cable. Gold pins of plug should face the installer. Otherwise, the resulting connection will be miswired. Terminate the plug using a modular plug-crimping tool by [inserting] it into the RJ-45 die in the tool, and squeeze the handles firmly.
“All Category 3 (16 megahertz), 5e (100 megahertz), and 6 (250 megahertz) UTP cables that connect computers and other networked equipment together are terminated with an eight-position modular plug. The completed patch cable is terminated with an RJ-45 connector on each end,” Meader said.
Rick Salvas, Ripley’s national accounts manager, said: “For CCTV applications, BNC connectors, along with Series 59 coax cable dominates the video surveillance arena. The Series 59 coax provides excellent video transmission without any noticeable loss in video quality up to approximately 750 feet. The common BNC connector types used are hex crimp, compression, and twist-on and are designed with a unique twist-and-locking feature to provide a secure connection to the cable interface.
“To properly prepare coax cable, the installer will need three tools: a coax cable cutter, a coax stripper and a compression/crimping tool. The coax cutter should ideally be of the design that maintains the cable’s roundness as much as possible while also providing for a faster and better quality stripping preparation. Many stripping tools allow for the replacement of the blade cartridge when needed without the need to replace the entire tool.
“The choice of BNC connector will dictate the type of coax stripping tool. Connector manufacturers may require three-step prep or two-step prep, which will determine the choice of coax stripper. Using a factory preset designed tool, the installer does not have to make any adjustments to the tool that could cause improper preparation and result in a poor-quality termination and possible equipment failure.
“Twist-on type connectors do not require a crimp or compression tool but still require a cable cutter and a coax stripper to prepare the cable for acceptance of the twist-on connector,” Salvas said.