The Temperature Effect: How Ambient Temperature Affects Electrical Wires

Electrical wires play a crucial role in powering our daily lives. They are used to transmit electricity from the source to the end-user.

However, the ambient temperature has a significant impact on the performance of electrical wires.

In this article, we will discuss the effects of ambient temperature on electrical wires from both safety and electrical points of view.

effects of ambient temperature on electrical wires

Conductor Resistance

The resistance of a wire increases as the temperature increases. This is due to the fact that the wire’s conductor material has a positive temperature coefficient of resistance. As the temperature increases, the resistance of the wire also increases. This can lead to power loss and increased energy consumption.

Insulation Degradation

The insulation surrounding electrical wires can degrade at high temperatures. This can result in reduced electrical performance and even short circuits.

Over time, the insulation can become brittle, which can cause it to crack and break, exposing the conductor to the environment. Read my other article insulation damage, causes, effects and preventions. for more information.

Thermal Expansion

As the temperature of a wire increases, it expands. This can cause the wire to sag, which can be dangerous.

In overhead power lines, this can cause the wire to come into contact with tree branches or other objects, leading to a potential hazard.


If a wire is exposed to high temperatures for an extended period, it can overheat. This can cause the insulation to melt and even lead to a fire.

Overheating can occur due to many reasons, such as overloading or poor ventilation. Read my article Cable overheating for more in-depth information.

Thermal Cycling

Thermal cycling refers to the repeated heating and cooling of a wire. This can cause the wire to expand and contract, leading to material fatigue. Over time, this can cause the wire to break, which can be dangerous.

Safety Measures

To prevent the adverse effects of ambient temperature on electrical wires, it is essential to take appropriate safety measures. These include:

  • Proper wire sizing
  • Proper installation and insulation
  • Adequate ventilation
  • Regular maintenance and inspection

Let’s go in details;

  1. Proper wire sizing: Choosing the appropriate wire size is crucial for preventing overheating and other temperature-related hazards. If the wire is too small for the load it carries, it can overheat and potentially cause a fire. Conversely, if the wire is too large for the load, it can lead to poor performance and wasted energy. It is essential to follow the appropriate wire sizing chart or consult an electrician to determine the appropriate wire size.
  2. Proper installation and insulation: Proper installation and insulation of electrical wires can prevent insulation degradation, overheating, and short circuits. It is important to ensure that the wires are installed correctly, with adequate spacing and supports to prevent sagging. In addition, it is crucial to use the appropriate type of insulation for the specific application and environment. Insulation should be checked regularly for damage or wear and replaced as needed.
  3. Adequate ventilation: Proper ventilation can prevent overheating and ensure that the wires are operating at a safe temperature. It is important to ensure that the wires are not enclosed in a confined space or covered with insulation or other materials that can restrict airflow. Adequate ventilation can also prevent the buildup of potentially flammable gases or fumes.
  4. Regular maintenance and inspection: Regular maintenance and inspection can identify potential hazards before they become a problem. It is important to inspect the wires regularly for signs of damage, wear, or corrosion. In addition, it is essential to check the connections and fasteners for tightness and proper alignment. Regular maintenance can prevent potential hazards and ensure that the wires are operating at optimal performance.


In conclusion, the ambient temperature can have a significant impact on the performance of electrical wires.

From increased conductor resistance to insulation degradation, it is important to be aware of the potential hazards and take the necessary safety measures to prevent them.

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