Cabling

Unshielded Twisted Pair (UTP) Cable Installed in Metal Conduit

To install UTP cabling in a grounded metal conduit, consider the following:

• Use conduit composed of ferrous metal. Aluminum conduit is unacceptable as it provides little or no protection from EMI.
• Use conduit throughout the system from junction box to junction box to ensure an adequate ground return path.

Polyvinyl Chloride (PVC) Conduit

When cables are buried below the floor level, the use of PVC conduit is permitted. When using PVC conduit in concrete flooring, the following guidelines apply:

• Locate the PVC conduit at least six inches below the surface of the floor.
• Locate the PVC conduit at least six inches from other nearby conduits.

Cable Damage

Mechanical damage to cables is usually evident during installation. Outdoor cable runs are especially vulnerable, as exposure to sunlight, rain, and wind-induced flexing can cause deterioration. Avoid kinking or sharply bending the cable; the bend radius should be at least four times the cable’s outer diameter.

Lightning

Lightning does not need to strike cabling directly to cause system damage or disruption. Nearby lightning strikes generate strong electromagnetic fields that can induce voltages in data transmission cables, leading to interruptions or damage. In areas prone to frequent thunderstorms, use grounded ferrous metal conduit. When installing shielded cables, minimize lightning effects by running cables as close to ground level as possible.

Electrical Motors

Motors of various sizes are commonly found in restaurants and hotels. When routing cabling, use a grounded ferrous metal conduit if the cable is within two feet of motors up to 1/4 horsepower, or within six feet of motors larger than 1/4 horsepower.

Radio Frequency Interference (RFI)

The likelihood of RFI depends on several factors, including transmitter power, building location, construction materials, and the physical placement of power and data transmission cables.