The best solution for cable conduit would be in a chemical plant and oil refineries. They fell that there is better protection from the wires being in the conduit from chemical spills. Where the cable tray is used in open space manufacturing and in paper manufacturing warehouses. The cable trays are kept high enough to protect them from damage and are easily accessed to run the cable.
With direct burial, the cables are buried anywhere from 24 inches to 48 inches in depth. The cables are run through a steel conduit or are a special type of cable that resists moisture and corrosion. This is mainly used in new construction of homes and commercial buildings and depends on local and state codes. Aerial installations are generally used in pre-existing conditions: like older homes and markets. A good example of aerial installation would be in the older sections of large cities and most of the older small towns throughout the Midwest.
First off you need to make sure the cables you are using are fire resistant. You must also caulk all holes drilled into walls. You also need the proper fire extinguisher for the area of electronics and work environment, whether this be a Class A, B, C, or D. To prevent a short from happening in your network you must make sure that anything that needs to be ground is grounded. The code for fire resistance by the NFPA (National Fire Protection Agency) is NFPA 1. The code for grounding codes are NEC article 250.1, 250.2 and 250.3.
