Size of Cable for a Given Load

Size of Cable for a Given Load Points : Size of Cable for a Given Load To determine the correct size of a cable for a given load, we concern the tables of electric cables. In this, current carrying capacity of a able,’ Voltage drop in cable: temperature factors are given. Some points are given below, are very important to determine the correct size of a cable.

Current Carrying Capacity of a Cable

Current Carrying Capacity of a Cable Points : Current Carrying Capacity of a Cable The current carrying capacity of cable is limited by electrical and chemical deterioration of the insulation at high temperatures.

Voltage Grading of cable

Voltage Grading of cable Points : Voltage Grading of cable Generally wiring cables are manufactured in two voltages grading such as low and medium. The two grads are termed as 250/440V and 660/1100 voltage grade. For wiring purpose the cables are designed for maximum1100 V capacity. If there are two cables which have same conductor size insulation size is different. The insulation of medium voltage cable is thicker and the low voltage cable has thin insulation site. The minimum thickness of the insulation is determined by the supply voltage.

Types of cable W.R.T core

Types of cable W.R.T core Points : Types of cable W.R.T core “In electric cables, the insulated conductor is known as core.” If a cable is required containing more than one insulated core that is a multi core cable. A cable can have many numbers of cores but the most common are single, twin, three and four core cables.

Classification of Cables w.r.t Insulation

Classification of Cables w.r.t Insulation Points : Classification of Cables w.r.t Insulation The construction of cable is that to envelope the conductor a non-conducting material. The insulation is this material in which the electricity can’t flow. For cable insulation there are only insulation material are used such as. P.V.C, mica power, Fiber etc. The purpose of insulation is that to provide protection electric chock, leakage of current and fire etc.

Choice of Cable

Choice of Cable Points : Choice of Cable The essential components of a cable are a metallic conductor of low resistivity to carry the current and insulation around cable which provide dielectric medium for isolating conductors from one another and from their surroundings. It is recommended that always choose the correct size of cable that is big enough to prevent the development of dangerous temperatures and also big enough to avoid wasted power in the form of excessive voltage drop. This wasted power is used in heating the cable causing the temperature may be rise sufficiently to damage or even destroy the insulation of the cable and also efficiency of electrical devices is decreased. Cheaper cables are not good for electric wiring because the power loss and voltage drop in these cables are very high.
To choose the correct size of cable for electric wiring, some important points to be remember.

Tinning

Tinning Points : Tinning Copper and rubber, when brought into contact, react upon one another chemically. It was formerly thought that this action was due entirely to the sulfur in the rubber compound combining with the copper. Pure rubber, however, also reacts with the copper.