In today's world and with the advancement of technology, cables
are one of the most useful human products that help humans to make
life easier. Cables have a variety of applications and their
effects can be found in almost all buildings, industries and
types. Products such as life supplies, tools, electrical
appliances, etc. were felt around him. Cables are introduced based
on the type of application they have. For example, a tow cable is
a type of interconnected cable from special wires used in its own
industries. Cables that pass electrical conductors are called
power cables. power cables are very different from cables. They
are used in the telecommunications industry. Gold is the best
conductor of electricity, but due to the high cost of this type of
metal, it is generally used in cables to pass conductors of copper
Cables consist mainly of three main components: conductor,
dielectric, and sheath. The conductor in Cable provides the flow
direction. Insulation or dielectric resistance is resisted by the
service voltage and separates the conductor from other objects.
The sheath does not allow the conductor to access the cables and
protects the cables from all external influences such as chemical
or electrochemical attack, fire, etc. The main components of
electric power cables are described in detail below.
What is the definition of an power cable?
The cable used to transmit and distribute electrical
energy is called an power cable. An power cable consists
of two or more wires or electrical conductors held in a
protective or insulating sheath. It is possible. It is
safe to say that in the electricity industry, it is the
responsibility of these wires and cables to transfer and
distribute energy. Gold metal has the best electric
current, but due to the high cost of this type of metal,
it is commonly used in cables to pass conductors of
copper and aluminum. Electrical cables are classified
according to specific and many standards. These
standards include use based on application, location,
environmental factors, voltage value, current value, and
power cable classification in a nutshell:
power cables are classified according to the amount of
pressure and voltage level as follows:
1- Fireproof cable .
2- Power Instrumentation cable.
3- Construction power cable .
4- Poor voltage power cable .
5- Medium pressure power cable .
6- High voltage power cable .6- power cable فشار قوی .
There are two categories of power cables depending on the
1- Armed power cable .
2- Unarmed power cable .
What is the definition of armed cable and unarmed cable?
Armed Cables: Power cables that are resistant to the
pressure and influence of ambient moisture and shocks
and other environmental factors and have steel strips
and lead coils are called armed cables.
unarmed cables: Those power cables that have a
structural structure unlike armed cables and are only
electrically insulated are called unarmed power cables.
Category of power cables based on the type of operation
and places used:
1- Ground power cable
2- Air power cable
3- Construction power cable
What is a ground power cable?
This type of power cable, as its name implies, is used
for places where the cable must pass through the soil
and the ground, and the material used in its conduction
is generally copper and has PET insulation and sheath.
The wire is reinforced with steel tape.
What is an air power cable?
These cables are used both for the bulk passage of
electricity from power plants and for the specific
passage of electrical voltage that must be hung in the
air and on the beams. Generally, these cables use a
string of galvanized steel wire under the cable sheath
in line with the rest of the wires.
What is a building power cable?
Everyone is generally familiar with this without the
need for a specific description. Many of these power
cables are used in construction, and the conductor is
generally copper and has pvc insulation.
What is the structure of an power cable?
Building a standard cable depends on many materials. The
most important features to consider are:
1- The place or location of the used power cable and its
2- The type, as well as the amount of voltage and
current that is to pass through the power cable.
There are other things that are not the same standard
for everyone, but in general, the power cable consists
of two main and important parts:
1- conductor Cable
2- Cable insulation
Note: Sometimes an power cable with a cable conductor
and cable insulation does not have the characteristics
of a suitable cable, and for these purposes, knauf or
armor and shield are used in the construction of the
power cable to provide more protection. So with the
above explanation, we conclude that the power cable
should have four parts.
1- conductor Cable
2- Cable insulation
3- Cable or armor shield
4- shield or jacket Cable
The classification of cables varies depending on the
shape, cross section, material and number of conductors,
voltage, type of installation and insulation used in the
What is a cable conductor?
In general, a conductor is needed if we want electricity
to pass through a small device or to create power lines
that supply an entire city. A conductor is a material
that allows the electric current to pass freely. In the
case of an electrical system, a "conductor" specifically
refers to a piece that transmits electricity from a
source to the load of a device or place of use.
When an electric charge is applied, metals provide the
best conductive properties. That's why metals are the
best choice for conductors in electric cables. Although
we are all accustomed to using copper as the most
conductive, the best metal conductor is silver. But due
to the high price of silver, copper is often used. Other
metals such as aluminum, gold, steel and brass are also
conductive, but are not as effective as copper and
silver, and the use of these metals in power cables may
have other side effects. Pure that has acceptable
flexibility or is made of aluminum or its special
The conductor used in the power cable has different
shapes. The shape of the conductors inside the power
cable is marked with the following abbreviation on the
re: round single string
rm: round a few strings
Se: Single string triangle/p>
Sm: A multi-string triangle
What is cable insulation?
Electrical cable insulation is a non-conductive material
or material that is resistant to electric current. It is
often called a dielectric in radio frequency cables. The
insulation resists electrical leakage, prevents the wire
from coming into contact with other conductors, and
protects the integrity of the wire material by
protecting it from environmental threats such as water
and heat. The safety and effectiveness of the wire
depends on its insulation. The use of insulation around
a conductor in an electrical cable is used to separate
the conductors. Most electrical cable insulation is made
of polymer and sometimes oil-impregnated rubber. The
material and number of layers are selected according to
the type of power cable and its application.
The most important types of cable insulation are:
1- Polyvinyl chloride or plastic (PVC) cable insulation
2- Semi-Rigid PVC cable insulation (SR-PVC) .
3- Polyvinyl chloride cable insulation Plenum (Plenum
4- Polyethylene cable insulation (PE)
5- Polypropylene cable insulation (PP)
6- Fluoropolymer cable insulation
7- Rubber cable insulation
8- Insulation of cable paper impregnated with special
The most common dielectrics in paper power cables are
impregnated paper, butyl rubber, polyvinyl chloride
cable, polyethylene, and cross-linked polyethylene.
Paper insulation cables are preferred because their
current carrying capacity is high, they are generally
reliable and have a longer life.
The dielectric composition used for the cable must have
the following properties:
■ Insulation must have high insulation resistance.
■ It must have a high dielectric strength so that it
does not allow leakage current to pass through it.
■ The materials must have good mechanical strength.
■ The dielectric material must be able to work at high
■ It should have low thermal resistance.
■ It must have a low power factor.
Cables used for underwater and wet soils should use
synthetic dielectrics such as polyvinyl chloride,
polyethylene, and so on. Also, this type of dielectric,
with its good dielectric resistance, is capable of low
power loss and low thermal resistance.
Electric cable inner cover:
It is used to protect the cable against the moisture
that affects the insulation. The cable sheath is made of
lead alloy, and these resistors withstand the internal
pressures of the pressurized cables. The material used
for the interior coating must be made of non-magnetic
Aluminum sheaths are also used in power cables because
they are cheaper, lighter in weight, and have higher
mechanical strength. Cables and telephones filled with
oil use corrugated aluminum corrugated cables because
they have better bending properties, reduced thickness
and less weight.
Cable protective cover:
Lead sheath cables are damaged by corrosion and
electrolyte when placed directly on the ground. Fiber
vinyl chloride is used to protect cables against
corrosion layers of fiber materials such as paper,
hessian, etc. The layers of fibrous material that are
dispersed with the waterproof compound outside the power
cable are called servers.
What is the difference between an power cable or a power
With all the explanations given in this section, it is
easy to say that the power cord consists of one
conductor, but the power cable consists of several power
wires and several conductors.