What is the maximum allowable conductor length run without support?

The maximum allowable conductor length run without support is indeed 15 feet. This rule is stipulated to ensure safety and to maintain the integrity of electrical installations. Conductors that are too long without support can sag or become subject to mechanical damage, which could lead to insulation failure, short circuits, or other hazardous situations. Maintaining this length limitation is essential for preventing such risks and ensuring that the electrical system remains secure and reliable.

This standard dictates that conductors should be adequately supported at intervals or fixed points to minimize the potential exposure to physical stress and environmental factors. The specification of a 15-foot limit represents a balance between flexibility in installation and ensuring safety and stability. Therefore, following the NEC guidelines regarding conductor support is critical in electrical work and installations.