Who must check ground switches before a transmission clearance?

The correct choice emphasizes the importance of having qualified personnel responsible for ensuring ground switches are checked before a transmission clearance. A Class A employee typically possesses the required training and expertise necessary to safely and effectively check ground switches, thus minimizing the risk of accidents or errors during operations. This role is critical in maintaining safety protocols and ensuring that all equipment is functioning correctly before any work is performed on the electrical system.

The requirement that a Class A employee performs this task is in place to ensure that someone with the appropriate knowledge and skills is involved in the process. This includes understanding the mechanical and electrical systems tied to the switches, as well as the necessary safety precautions that must be followed.

In contrast, other options may imply that individuals without the required qualifications, such as onsite workers who may not be fully trained or only certain individuals like a supervisor, could perform this task. However, allowing anyone without specific qualifications could lead to oversight of important safety checks, increasing the risk of accidents. Thus, requiring a Class A employee for this responsibility underlines the critical nature of expertise in maintaining safety in electric systems.