To avoid inductive heating in metallic raceways, how must circuit conductors be arranged according to NEC?

Running all circuit conductors in the same raceway is crucial to minimizing the effects of inductive heating. When conductors are grouped together, they can cancel out magnetic fields generated during current flow, which reduces the likelihood of heat buildup. This arrangement ensures that any potential inductive currents are kept to a minimum, promoting efficient operation of the electrical system.

Inductive heating occurs when varying magnetic fields interact with metallic objects, which can generate unwanted heat. By keeping circuit conductors together, the NEC aims to standardize practices that mitigate these risks, thereby enhancing safety and performance in electrical installations.

In contrast, separating conductors into different raceways may interfere with this cancellation effect and can lead to increased inductance and heating. Isolating each conductor or twisting them together does not mitigate inductive heating effectively in the same manner as running them together in a single raceway does. Therefore, the arrangement specified in the NEC is essential for maintaining safe and efficient electrical systems.