What is the primary concern with the presence of aluminum wiring?

The primary concern with aluminum wiring lies in its susceptibility to overheating and the associated fire risk. Aluminum, compared to copper wiring, has a higher resistance and expands more when heated. These properties can lead to poor connections at terminals, which may create arcs or overheating under load. This increased risk of overheating can subsequently result in electrical fires, particularly at outlets or junctions where connections may not be tight.

The safety implications of using aluminum wiring are significant, prompting regulations and guidelines to ensure any aluminum wiring is properly installed and maintained. While its weight, susceptibility to rust, and installation difficulty can pose concerns, they do not directly lead to the critical hazard of fire that arises from overheating connections. This makes the concern about aluminum wiring's potential for causing electrical fires the most pressing issue among the options provided.