The main reason for conduit is because of the high protection it offers. Cable tray installation is cheaper and more flexible than using conduit. It is easier to access the cables in a tray than when installed using conduit. The conduit can be buried concrete or on top of it. Installing conduit is harder than installing with trays. Conduit would be used when the cables are going to be set in place for sure and require protection. Tray installation would be for when cables would need to be changed more frequently and does not require being underground.
There are three types of installations for cables and they are direct, aerial and blown fiber installations. Direct burial is cable which is buried directly underground. It does not need any special covering or pipe to be buried. This type of cable is less expensive and easier to burry but the downfall is it can be easily cut during a dig. They can also be rodent protection in direct burial if required. Audio and data information can be transmitted through this type of cable. Main reason of direct-buried cable is such that there is no need to provide any type of exterior protection. The leading advantage of direct-buried cable is that this result can be set up with relatively little effort, since there is no need to prepare the ground where the cable is laid by putting in piping or making other adjustments. Next cable installation is aerial installation. This is a type of installation is when the cables are installed using utility poles or pylons, and provides ease of setting up and decreases time and cost. Mainly used for telecommunications, aerial installation can be used for power transmissions. Environmental changes can affect the areal cables. Thirdly, blown fiber installation is flexible letting changes be easily done at a later date from the length of the fiber to the changing out of the type of fiber. Putting up a telephone cables is a good example of areal and direct burial is when the cable has to go under a road or sidewalk. Direct burial and aerial compare in that they both can be used in the air. When putting up cables of any nature, there are regulations that need to be followed. Some of these guidelines are: never kink the cable, do not exceed recommended bend radii, during or after installation, never crush the cables, optical fiber cable should not rest against sharp edges, and must be “swept” around corners, make sure all cables are secure in any installation, plan all cable routes before beginning, making sure the cable will not be exposed to hazard, and meet the terms with all regulatory requirements and fire codes. The National Electric Code or NEC sets the rules and regulations.