Red Seal Powerline Technician Practice Exam

What materials are commonly used for overhead power lines?

1. Steel and plastic

2. Aluminum and copper

3. Iron and glass

4. Wood and fiberglass

The correct answer is: Aluminum and copper

Overhead power lines primarily utilize aluminum and copper due to their excellent electrical conductivity, lightweight nature, and resistance to corrosion. Aluminum is favored for its low weight and cost-effectiveness while still providing acceptable conductivity for many utility applications. Copper, although heavier and more expensive, offers superior conductivity which is vital for efficient power transmission, particularly in smaller or specialized applications. The other materials listed do not serve the primary role of conducting electricity in overhead power lines. Steel, while strong, is typically used for structural components such as poles and towers rather than the conductors themselves. Plastic and fiberglass are utilized for insulation and protective coatings but do not conduct electricity effectively. Iron is generally too heavy and prone to rusting for use in overhead lines, and glass is not practical for overhead conductors. Thus, aluminum and copper stand out as the materials of choice for their desirable electrical and physical properties.