Which type of connectors are prohibited on AC grounding conductors?

Friction type connectors are prohibited on AC grounding conductors primarily due to their potential to create unreliable connections over time. Such connectors rely on pressure to maintain contact, which can lead to loosening due to vibrations, thermal expansion, or simply aging. These conditions can compromise the integrity of the ground connection, resulting in inadequate grounding, which is critical for safety in AC systems.

In contrast, other types of connectors, such as screw terminals, provide a more secure and stable connection due to their design, which allows for a firm grip on the wire. Quick-connect terminals, while easier to use in many applications, are typically designed for low-current connections and can be acceptable in specific contexts but are not recommended for grounding purposes. Open wire connectors may also be employed in particular circumstances, given proper application and installation practices.

The focus on ensuring reliable and durable connections in grounding systems underscores the importance of using appropriate connection methods to maintain safety and functionality in electrical installations.