Basically electrical cable is a conductor to carried electricity from one place to another place.Cables provide a reliability and compacting method of transmitting power from generator to end user or consumer.
Cables are installed in open air on tray,racks or ladders, underground, or underwater as in the case of submarine cables.We can found many different types of cables or wire suitable with out application and working area.
The fundamental concern of power cable engineering is to transmit current economically and more efficient. The choice of the conductor material, size, and design must take into consideration such items as:
What is the electric cable or wire important aspects?
- Current carrying capacity
- Voltage stress at the conductor
- Voltage regulation
- Conductor losses
- Bending radius and flexibility
- Overall economics
- Material considerations
- Mechanical properties
Over the many years,manufacture has been a progressive improvement in the materials used in the construction of cables, especially in the non-metallic materials.To get a high quality of products,several necessary requirements needs :-
a) To maximize the conductor temperature and hence the power transmitted.
b) To provide high resistance to mechanical wear and tear, both during the laying of the cables, and in their on-going use when they may be disturbed in the future.
c) To withstand the effects of chemical attack from their environment
d) To withstand the damaging effects of steady state and transient over voltages.
e) To withstand the impact of heat from the environment when exposed to fire and high radiant temperatures.
f) To withstand freezing temperatures
g) To be resistant to ultraviolet light when exposed to bright sunlight.
Not all of the above requirements are needed for a particular plant. The specification of the cable and its materials should take account of the changes in its environment.
The conductor current rating should be based on the worst-case conditions if the cable is to be fully utilized and expected to give a long life time of service.