Is it permitted to run a branch circuit from the neutral bar in a 120/240-volt panelboard for a 208-volt load?

Running a branch circuit from the neutral bar in a 120/240-volt panelboard for a 208-volt load is not permitted. This is primarily due to the differences in voltage configuration. A 120/240-volt panelboard is generally designed to provide single-phase loads at 120 volts or 240 volts.

A 208-volt load typically comes from a three-phase system, which is fundamentally different from the single-phase configuration. The phase-to-phase voltage in a three-phase system can reach 208 volts, while the neutral bar in a 120/240-volt system is designed to facilitate returns for 120-volt single-phase loads.

Connecting a 208-volt load to a source that's not aligned with its voltage requirements can lead to improper operation, potential equipment damage, and safety hazards. Compliance with the National Electrical Code (NEC) and proper electrical design principles is essential to ensure that electrical installations are safe and appropriate for their intended loads.