Power cables, as you must be aware of already, are permanent arrangements with the help of which electric power can undergo transmission.
As mentioned, there are many types of such cables, and each of them is designed and made according to the application it would serve. But all cables share a common feature of components such as conductors, insulation, and a protective sheath.
There are certain important factors that determine the construction of all types of power cables, and the material to be used for the same. These include the voltage the cables would operate on, the magnitude of current to be used, and the factors that are related to the environment in which the cables will be introduced.
The voltage factor is necessary to determine the thickness of the insulation, while the current decides the cross-sectional size of the conductor or conductors. And speaking of the environment, elements such as water, temperature, pressure, sunlight, chemicals, risk of mechanical impact, and the like, decide the nature of the outer jacket of the power cable.
Submarine Power Cables
It is easy to guess from the name itself that these power cables are utilized for carrying current under the surface of the water. Usually, these cables are used under salt water bodies, common examples being ocean, seas, straits, etc.
However, their design allows them to be used for projects beneath freshwater bodies, as well; for example lakes and rivers. Since these cables are laid on the seabed, their outer covering needs to be able to endure tremendous pressure and disturbances.
So keeping this in mind, it is made of a thermoplastic polymer called polypropylene which makes the power cable highly resistant to chemical solvents, bases and acids. More importantly, the cables are made of steel wires, which cut off risks of damage during installation under the water.
Nonmetallic Variant B Cables
This type of power cable is used to run through walls, under floors, through attics and so on. It is called so because of its sheath that is nonmetallic.
The material that is used to make the sheath holds properties that make it flame resistant, and resistant to moisture problems, sunlight exposure, mold or mildew, and corrosion. As metal is not used in these cables, they are easier to work with, and relatively cheaper as well.
These cables are relatively cheaper than those used underground, as no work of digging is involved. These cables are made resistant to ultraviolet rays, and all forms of weather.
Being completely insulated, electricians can work on these cables without any danger of an electric shock. Also, even if these cables fall, they will still work normally unless, the insulation is damaged.
Steel Wired Armored Cables
Widely used for transmission of electricity underground, power networks and cable ducting, these power cables consist of a conductor (plain stranded copper), insulation (cross-linked polyethylene), and bedding [made of polyvinyl chloride (PVC); required for separating the inner and outer layers of the cable].
The toughest part of these cables is their armor that is made of steel. Such a make allows these cables to be installed underground and in places of high stress. The sheath that is used for these cables is made of PVC, and provides further protection from damage.
Here we described a few basic properties about power cables, and there is certainly a lot more to learn. So in case you should look for more details, a professional electrician would be the best source of information to seek.