Are three-phase, 208Y/120V or 480Y/277V systems designed to supply nonlinear loads allowed according to the Code?

The National Electrical Code (NEC) recognizes that three-phase systems, such as 208Y/120V and 480Y/277V, can indeed supply nonlinear loads. Nonlinear loads are those electrical devices that draw current in a non-uniform manner, typically due to their usage of electronic components, such as variable speed drives, computers, and other digital equipment.

According to Article 210 and related NEC guidelines, these three-phase systems can be configured to correctly handle the harmonics produced by nonlinear loads. The Code encompasses provisions that ensure the safe and effective distribution of power to such loads without causing voltage drops or overheating of the electrical system. This allows for a broad range of applications, supporting various commercial and industrial environments.

The acceptance of these systems means that they are equipped to handle the unique challenges that nonlinear loads present, such as the creation of harmonics, which can lead to power quality issues. Consequently, the engineering standards for installation and the requisite protective measures outlined in the NEC assist in mitigating potential problems while ensuring compliance with safety and operational efficacy.

Therefore, the answer indicates an understanding that three-phase systems are suitable and permissible for feeding nonlinear loads as specified in the NEC.