Answer :
Final answer:
Aluminum wires must have a larger diameter than copper to achieve the same resistance per length. Due to aluminum's properties, special techniques must be employed when using it for service conductors. The smallest permitted sizes for overhead service conductors are 2/0 for copper and 4/0 for aluminum.
Explanation:
The question asks about the minimum permitted size for overhead service conductors made of copper or aluminum. When considering the use of aluminum instead of copper for service conductors, the aluminum wires must have a larger diameter to match the resistance per length of copper wires. While aluminum is cheaper than copper, this is not a significant drawback. However, aluminum does present challenges such as a higher rate of thermal expansion, which can lead to loose connections and fire hazards, as well as the fact that oxidation of aluminum does not conduct electricity, causing further issues. These challenges necessitate the use of special techniques and compatible components when working with aluminum wires.
In terms of American Wire Gauge (AWG), overhead service conductors are generally not permitted to be smaller than 2/0 copper or 4/0 aluminum. This corresponds to option 2 in the provided choices (2) 2/0, 4/0.
