When is a cable assembly shield permitted to serve as the required equipment grounding conductor?

A cable assembly shield can serve as the required equipment grounding conductor only when it is specifically designed for that purpose, which commonly applies to configurations like concentric strand or conductive tape. These designs allow for adequate conductivity and mechanical strength, ensuring they can safely handle fault currents and provide a reliable ground.

In other cases, such as when the shield is made of materials that may not have sufficient conductivity or structural integrity, or when the installation does not meet specific requirements, using the shield for grounding would not be acceptable. This ensures safety and compliance with electrical standards that seek to protect both equipment and personnel from electrical faults.