By Steven Totolo, President, Total Voice Control

Installation of wiring

With proper installation techniques, crosstalk, noise and signal quality are improved. Crosstalk occurs when conductors are located parallel to each other and the signal on one conductor is coupled to the other. Typically, two users will notice crosstalk when an outside phone conversation can be heard by one party, not the other. Noise from fluorescent lights, motors, or electrical appliances can be coupled onto the wiring. To reduce these problems, CAT5 and RG-6 cables should be kept at least 30 cm away from electrical wiring when they are parallel to each other as illustrated in Figure 7a. When cables cross, they should be kept at 90 degrees to each other (Figure 7b). Furthermore, electrical and CAT5 or RG-6 mounting boxes must be kept a least 30 cm from each other (Figure 7c), using at least one stud distance between each service (Figure 7d).

Cabling should be attached using hook clips or other wiring retainers that do not crush conductors. If there are many cables in a path, hangers should be affixed to support the bundle. Cable ties can be applied but should not be over-tightened. Excess tightening can pinch the wiring, whereas a loose tie will allow cables to slide easily back and forth within the bundle.

Using Velcro straps during the installation can ease cable pulling since they can be nailed to studs or joists. Cables can then be pulled through the loose opening with little force. Pulls should be made in stages when the paths are long or have many turns to reduced risks of damaging the wires and knotting. Never exceed a stretching or pulling tension more than 10 kg since this may cause the wire pairs to untwist.

Whenever cable bends are required, maintain a minimum turning radius of 4 times the cable’s outside diameter (for CAT5, approximately 2.5 cm; and for RG-6 and fibre, approximately 3 cm.)

Twisted pair cable must remained twisted as close as possible to the point of termination. Untwisting should not exceed a 1.25 cm for CAT5, or 7.5 cm for CAT3. The jacket of the cable should only be stripped back as much as required to perform the termination of individual pairs.

Fibre optic cables must be installed into housings with at least an extra 1 m of length for termination. The connection box must have the capacity to secure the cable in some form, but ensure a minimum-bending radius of 3 cm. Multimode connectors should be beige in colour, while single mode should be identified with blue connectors.

Cable runs must originate from point of use to a central location, usually a utility closet or near the location where services enter the home. This is referred to as "home run" cables. In other words, cables enter a service junction, or gateway, that interconnects phone, video, and network utilities to access points located throughout the home. Short interconnecting cable could then be used to link these services.

Part 2 - Properties of new wires
Index
Part 4 - Home services locations
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Steven Totolo is president of tvcAutomation, a home automation specialist and a member of the CABA Standards Committee. He can be reached at (613) 795-7117; fax (613) 737-5323; email: sales@tvcAutomation.com