How many support methods must be provided for each conductor at the top of a vertical raceway?

In the context of vertical raceways, the National Electrical Code (NEC) requires that each conductor must be supported in a manner that ensures both safety and functionality. The correct response indicates that one support method is mandated at the top of a vertical raceway for each conductor.

This requirement is designed to prevent undue stress on the conductors, which can occur if they are unsupported, especially in vertical installations where gravity can cause sagging or other tensions that could lead to damage. Supporting conductors appropriately helps maintain proper spacing, reduce the risk of mechanical damage, and ensure that electrical connections remain secure.

The NEC's focus on support methods is a vital aspect of electrical safety, as it ensures that conductors are appropriately secured, reducing the potential for electrical faults or hazards due to physical strain on the wiring system. Thus, providing one support method effectively sustains the integrity of the vertical raceway installation.