Aluminium Cables: Types, Advantages, and Limitations

Aluminium cables are widely used in power transmission due to their lightweight and cost-effectiveness. Different types of aluminium cables feature distinct structural characteristics and performance properties, making them suitable for various applications. This article introduces several common aluminium cables, analyses their advantages and limitations, and helps you gain a clearer understanding to select the most appropriate cable.

1. Common Types of Aluminium Cables

1.1 By Conductor Type

Aluminium Conductor Steel Reinforced (ACSR)

ACSR is a conductor made of aluminium and steel wire twisted around each other. The aluminium strands are for conduction, and the steel offers added mechanical reinforcement. This arrangement provides excellent engineering ability and withstands high tensile forces. ACSR is well-suited for long-distance high-voltage lines. It is widely used to cross rivers, canyons, and across electric transmission lines.

All-Aluminium Conductor (AAC)

AAC is a conductor made entirely of aluminium, offering lightweight properties and excellent flexibility, which facilitates construction and installation. However, its relatively low mechanical strength makes it unsuitable for long-distance or high-tension power transmission environments. AAC is more commonly used in urban areas or short-distance overhead lines to carry smaller stresses and loads.

All-Aluminium Alloy Conductor (AAAC)

AAAC cables are manufactured from aluminium alloy, enhancing strength and corrosion resistance while maintaining lightweight properties. Compared to pure aluminium, aluminium alloy offers superior resistance to tensile forces and external environmental impacts. These cables are widely used in overhead transmission lines, particularly in scenarios requiring medium spans and higher reliability.

Aluminium Conductor Alloy Reinforced (ACAR)

ACAR is an aluminium and aluminium alloy stranded conductor. While still providing the advantageous electrical conductive properties of aluminium, its mechanical strength has been enhanced through an alloying process, thereby extending its service life and overall durability. In addition, ACAR has an excellent compromise of strength, mechanical characteristics, and transmission properties compared to single-material conductors. So, it is very suitable for power transmission projects that have high performance requirements.

1.2 By Application

Aluminium Service Drop Cable

Aluminium service drop conductors are mostly used to connect power lines from the overhead pole power line outside a residential or other type of electrical building. They are usually constructed of AAC or ACSR conductors with insulation to provide protection for quick and easy installation.

Aluminium Building Cable

Aluminium building cables are widely used for the construction of houses, offices, and commercial buildings. They come with conductors insulated with PVC or any other good insulation technique to protect the electricity from harm.

Aluminium Armoured Cable

In hazardous conditions, aluminium armour cable is more protective. Its outer metallic sheath provides good protection against impact or friction damage while ensuring maximum electrical conductivity. Theretofore, such cable has been used extensively in construction sites or the like, which require protected wiring installations.

Aluminium Underground Cable

In underground or buried installations, use aluminium underground cable. With insulation and sheaths of moisture-proof, acid-resistant, and strong, shaking-resistant material, these cables can provide stable electricity transmission safely.

Solar Aluminium Cable

Solar aluminium cables are primarily used in photovoltaic power generation systems to connect solar panels to inverters or distribution equipment. Lightweight and weather-resistant, they adapt to various outdoor environments, ensuring long-term stable operation of solar systems.

1.3 By Insulation Material

XLPE Aluminium Cable

Cross-linked polyethene aluminium cable is referred to as XLPE Aluminium Cable. It can withstand high temperatures, and chemicals can be used for a long time.

PVC Aluminium Cable

PVC aluminium cable is insulated with PVC. It is cost-effective and easy to install, ideal for general power distribution.

1.4 By Voltage Rating

Low Voltage Aluminium Cable (LV)

Low-voltage aluminium cable (LV) is found in houses and small buildings. It is safe and reliable.

Medium Voltage Aluminium Cable (MV)

Medium voltage aluminium cable (MV) installation in a factory, city power grid. It can carry more power.

High Voltage Aluminium Cable (HV)

The high-voltage aluminium cable (HV) is intended for high-voltage long-distance power transmission. It has efficient dispatch and operates in arduous conditions.

2. Advantages of Aluminium Cables

Lightweight

Aluminium cables are much lighter than both copper and steel cables of equal diameter. These lightweight features are especially useful for your weight-critical applications like overhead power lines.

Excellent Conductivity

The electrical conductor of aluminium is only inferior to copper in terms of conductivity, which means it can transmit electricity very efficiently. For the majority of power transmission, aluminium offers relatively stable current flow for daily and industrial electrical requirements.

Cost-Effective

Aluminium is cheaper than copper, reducing the cost substantially in projects where cable is needed in vast quantities. Economical insulation with aluminium cables ensures system reliability and safety, and at the same time is a reasonably priced solution

Corrosion Resistant

Aluminium tends to react with oxygen, with the production of a natural oxide barrier, which prevents further reactions. This permits the use of aluminium conductors over a prolonged period of time in arduous atmospheres without having to spend undue amounts for maintenance and replacement.

Sustainable and Easily Recycled

Aluminium is an environmentally friendly, energy-efficient material that can be recycled over and over without losing its physical properties. Selecting aluminium cables saves natural resources and is in line with principles of sustainable development, thereby helping to reduce overall environmental impact.

3. Limitations of Aluminium Cables

Oxidation at Connections

Aluminium readily forms an oxide layer when exposed to air. Once oxidation occurs at cable joints, contact resistance increases, leading to heating and even overheating. This impairs power transmission efficiency and may pose safety hazards. Therefore, when you are using aluminium cables, measures must be taken to minimise oxidation effects, such as employing suitable connectors or protective materials.

Lower Tensile Strength

Aluminium has lower tensile strength than copper and is more prone to damage through stretching or heavy loads. This makes both aluminium conductors less secure than copper, in applications such as long span overhead lines or mechanically demanding environments, where it affects the overall design of the structure.

Creep and Cold Flow

Aluminium also creeps (cold flows) when under constant stress. Over a period of time, this may lead to loosening of the cable connection point and poor contact or even a power outage.

Thermal Expansion

Aluminium then has a larger temperature dependence of the thermal expansion coefficient compared to Copper. With large changes in temperatures, cable connections can be lost due to the expansion and contraction of the material. In the long run, there will be deterioration in power supply stability.

4. Conclusion

In general, aluminium cables are popular for use in both power transmission and building wiring. They do, however, have limitations. Your aluminium cable selections should be done with a full understanding of your project requirements and working environment. When installed properly and protected, aluminium cables are still a less expensive and convenient option for your power transmission project.

FAQ

What factors affect the current carrying capacity of aluminium cables?

The current-carrying capacity of aluminium cables is primarily influenced by several factors: the larger the cable's cross-sectional area, the greater the current it can carry; different insulation types exhibit varying heat resistance; and the cable's current-carrying capacity decreases at higher ambient temperatures. Additionally, installation methods play a crucial role—cables of the same specification exhibit higher current-carrying capacity when installed in free air with favourable heat dissipation conditions compared to direct burial. For instance, a 120-millimetre aluminium cable rated for 270 amperes in air carries only 255 amperes when buried.

Why do the aluminium cables’ temperature increase?

In aluminium cables, temperature rise is primarily due to the combined action of current and resistance. The cable heats up as current passes through it. Considering the small wire diameter, high resistance, and long working conditions of the conductor, the temperature increases with time. The cable also overheats if the heat dissipation is poor and the temperature cannot be released in a timely manner.

Why is aluminium cable used as an overhead cable?

Aluminium cables are particularly well-suited for use in overhead power lines due to the fact that aluminium is lighter than copper, which helps lower the load on towers and other supports. Aluminium is also much cheaper than copper, so large savings are to be made. While its electrical conductivity is 62% of slightly lower than that of copper, aluminium's light weight contributes to a greater power transmission capacity when compared with cables with larger cross-sectional areas. In addition, aluminium has high thermal conductivity, allowing heat to dissipate from the conductor surface; hence, aluminium is a great material for long-distance overhead line systems.

What is the difference between single-core and multi-core aluminium cables?

Aluminium single-core cables are made of one conductor, which provides a low-field structure and heavy-carrying ability that could be transported over longer distances. Multicore aluminium cables, however, are composed of a number of conductors with insulation or jacket to form a composite cable that is suitable for power or signal applications in building wire and cable as well as hook-up wire applications.