What must metal cable trays containing only nonpower conductors be through approved connections?

Metal cable trays that contain only nonpower conductors must be bonded or electrically continuous to ensure a reliable path for grounding and to minimize the risk of electrical shock. This is crucial for maintaining the safety and integrity of the electrical system. Bonding helps to equalize the potential across different conductive surfaces, thereby reducing the likelihood of hazardous voltages that could arise if parts of the system become energized inadvertently.

In this context, the requirement for bonding or electrical continuity specifically addresses the need for both mechanical stability and electrical safety. This prevents any accumulation of static electricity and ensures that any fault current has a low-resistance path back to the ground, promoting safer operation of the electrical equipment housed within the cable trays.

Other options, such as disconnection for maintenance, isolation for safety, or independent grounding, do not provide the necessary continuity or bonding that ensures safety and electrical integrity for systems utilizing nonpower conductors in metal cable trays.