What is a significant problem associated with Zinsco electrical panels?

Zinsco electrical panels are known for their poor connections to the bus, which is a critical issue. These panels were designed in a way that can lead to significant arcing or overheating, particularly at the point where the circuit breakers connect to the bus. This is due to a combination of factors, including the materials used in the construction of the panel and the design of the breaker connections.

Poor connections can create resistance, leading to excessive heat generation at the points of connection, which may result in the failure of the breaker or even a fire hazard. This issue is exacerbated over time, as corrosion and wear can further diminish the connection quality. The lack of reliability in these connections is a primary concern, making them a notable risk in homes using Zinsco panels.

The other options, while they may reflect common electrical issues, do not specifically capture the most significant problem unique to Zinsco panels, which is their inherently poor connections.