Florida InterNACHI State Practice Exam

In electrical supply systems, a phase 3 supply is characterized by three phases of alternating current (AC) along with a neutral conductor, which creates a total of four connected conductors. This configuration is commonly used for commercial and industrial electrical installations where balanced loads and three-phase power are desired for efficiency in operating motors and other heavy equipment.

The three phases provide three separate alternating currents that reach their peak values at different times, ensuring a more consistent power delivery. The additional neutral conductor is crucial for providing a return path for unbalanced loads and allowing for single-phase connections when necessary. This four-conductor system distinguishes it from other setups, such as single-phase supplies, which may have only two conductors (one live and one neutral) or higher phase systems that could involve more conductors.