overhead cable

Let’s Learn More About Overhead Cable Here!

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One of the most widely used electrical cables is undoubtedly an overhead cable.

We frequently see it gliding effortlessly over houses, and typically, this kind of cable is used to transmit data or electricity between different residential buildings.

In today’s society, in order to live comfortably, we all need access to electricity and information. You’ll probably need a line cable to reach them.

Unfortunately, it can be difficult to find one that meets your individual needs. When selecting the best option, you must take into account several factors, just like with other electrical cables.

Continue reading to learn the basics of overhead cable and find out which one is the best for you!

What Is Overhead Cable?

overhead cable

The phrase “overhead” typically refers to something that is in the sky or above the head.

So, to put it simply, an overhead cable is any cable that you can install in the sky above your head.

Anyone who doesn’t have any experience with electrical cables might think that any electrical wire is adequate for overhead installations.

This presumption is incorrect.

An overhead electric cable is perfect for “in the air” setups due to a number of essential characteristics. Any attempt to substitute a regular wire for an actual overhead one will not go well.

Conductor Materials In Overhead Cable

1.  Copper


Copper has a higher tensile strength and high conductivity. Therefore, hard drawn stranded copper is a fantastic choice for overhead wires.

Because copper has a high current density, it can carry more current per unit of cross-sectional area.

As a result, the cross-sectional area of copper conductors is significantly smaller. Copper is also strong and has a high scrap value.

However, copper is rarely used for overhead power lines because of its greater price and lack of supply.

2.  Cadmium-copper alloys

Cadmium-copper alloys

These alloys have between 98 and 99 percent copper and up to 1.5 percent cadmium.

When 1% of cadmium is added to copper, the conductivity is reduced by only around 15% while the tensile strength is increased by up to 50%.

Cadmium-copper conductors can therefore be suitable for extraordinarily large spans.

However, these conductors might not always be cost-effective due to the high price of cadmium.

3.  Aluminum


For the same resistance, aluminium has a conductivity of around 60% that of copper, meaning that the diameter of an aluminium conductor is roughly 1.26 times greater than that of a copper conductor.

The weight of an analogous copper conductor is almost twice as much as that of an aluminium conductor.

Additionally, aluminum’s tensile strength is lower than copper’s.

Aluminum outperforms copper when all the relevant factors—cost, conductivity, tensile strength, weight, etc.—are taken into account.

As a result, aluminium is a material that is commonly utilised for overhead conductors.

4.  Other materials

There are numerous additional metals and alloys that can conduct electricity.

Silver is more conductive than copper, but it is rarely used because of its high cost. A conductor may also be made of galvanised steel.

Steel has a very high tensile strength, but due to its poor conductivity and high resistance, steel conductors are not suitable for efficiently transmitting power.

At times, high strength alloys such as phosphor-bronze may also be used in harsh environments.

Related Article

Underground Cable: How Important It Is?

Types of Overhead Cable

type of overhead cable

1. AAC : All Aluminium Conductor

This type is also sometimes known as ASC (Aluminium Stranded Conductor).

It is constructed of aluminium electrical conductor grade, or EC grade, strands. The conductivity of an AAC conductor is 61% IACS (International Annealed Copper Standard).

AAC has a limited application in transmission and rural distribution lines while having an excellent conductivity due to its comparatively low strength.

Urban locations, where areas are typically small but better conductivity is necessary, can use AAC for distribution.

2. AAAC : All Aluminium Alloy Conductor

Aluminum alloy 6201, a high strength Aluminum-Magnesium-Silicon alloy, is used to make these conductors.

This alloy conductor combines improved mechanical strength with strong electrical conductivity (approximately 52.5% IACS).

AAAC can be used for distribution since it is less heavy than ACSR of equivalent strength and current capacity.

It is not typically favoured for transmission, though. Additionally, due to its outstanding resistance to corrosion, AAAC conductors are suitable for usage in coastal areas.

3. ACSR : Aluminium Conductor, Steel Reinforced

A spiral-wrapped layer or layers of high purity aluminium (aluminium 1350) wires make up an ACSR, which has a solid or stranded steel core as its base material.

The core wires might be made of steel that has been coated with zinc (galvanised) or aluminium (aluminized).

Thin coatings of galvanization or aluminization are applied to steel to prevent corrosion.

Additional mechanical strength is provided by the center steel core, which also reduces sag relative to all other aluminium conductors.

The steel percentage of ACSR conductors ranges widely, from 6% to 40%. Where greater mechanical strength is required, such as a river bridge, ACSR with a higher steel composition is chosen. The use of ASCR conductors is fairly common for all transmission and distribution needs.

4. Aluminium Conductor, Alloy Reinforced

Aluminum-Magnesium-Silicon alloy (6201 aluminium alloy) core is wrapped with strands of high purity aluminium (aluminium 1350) to create ACAR conductor.

Compared to equivalent ACSR conductors, ACAR offers superior mechanical and electrical qualities.

Both overhead transmission and distribution lines can use ACAR conductors.

5. Bundled Conductors

When only one cable per phase is utilised, transmission at very high voltages (let’s say above 220 kV) might cause severe corona loss and excessive interference with surrounding communication lines.

This is such that corona loss and interference issues can be caused, as the electric field gradient at the surface of a single conductor at the EHV level is large enough to ionise the surrounding air.

By using two or more conductors per phase in close proximity, the electric field gradient can be greatly decreased.

Bundled conductors are two or more conductors per phase that are joined at regular intervals by spacers.

Two conductors are shown bundled together in each phase in the figure to the right.

For increasing voltages, the number of conductors in a bundled conductor increases.

How To Install A Pole? 

You may want to know how overhead cables provide electrical supplies to buildings, right? 

In general, overhead cables need to have a support; utility pole to “distribute” the electrical supplies to public facilities such as electrical cable, fiber optic cable, and related equipment such as transformers and street lights.

In this section, we will be adding more information about pole installation; for instance, its installation method.

1.  Auger

overhead cable

First step is to determine the location for a placement of the pole base. You need to find a safe and vast space so that you can auger a hole.

Besides, this action is needed to ensure one’s safety.

In order to make sure that the base stays, you need to place a 6-inch foundation of crushed stones at the bottom of the hole.

2.  Place

Next step is you need to connect a lifting device to the base. This action is needed so that you can place the pole base.

To make this “task” easier and quick, you can use an excavator. While it does the “task”,  the employees need to level the base and run the wires and conduits.

3.  Backfill

overhead cable

Lastly, backfill around the base. In order to ensure the backfill is compact, it needs at least a 6-inch of standard compactor filled in the excavated hole.

Once the steps are complete, the poles and lighting can be mounted and turned on.

How To Ensure Safety During Overhead Cable Installation?

overhead cable installation

Before installation

  1. Proper plan between parties especially cable route survey.
  2. Be clear about electrical power cables and fibre optic cables on joint-use poles
  3. Any dead-end pole must be examined carefully to avoid any problem during cable installation.
  4. Do not make any installations during wet conditions and cable installation tools must be used to prevent unexpected accidents.

During installation

  1. Ensure cable, installation tools, and equipment are good condition.
  2. Be cautious of potential electrical hazard and area inside the cable loop is clear of anything.

setia urusharta

​​Now that you are aware of the basics of overhead cables, let’s choose a more secure, dependable, and affordable cable solutions.

Have you heard of Setia Urusharta Sdn. Bhd?

We are a qualified engineering service provider dedicated to providing services for the engineering industry in Malaysia.

We supply and install underground cable, overhead cable, and HDD in relation to interconnection facilities. Here, services for jointing and terminating are both offered.

According to our mission, customer pleasure is what keeps our service operating.

We strive to maintain and guarantee that we only provide the best services with our core team of vibrant people who are passionate and dedicated.

In addition, situated in Kajang, Selangor, we also provide additional engineering services like:

  • Construction services
  • Installation and repair of large pipes
  • Alternative energy

Not only that, we also offer integrated facilities management-related services like:

  • Facilities engineering maintenance
  • Cleaning services
  • Upkeep of the hardscape and softscape

Interested in our service? Click here to contact us now!

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