According to NEC® standards, how high must the ceiling be if the bottom of a 277/480-volt panel is 38" AFF?

Under the National Electrical Code (NEC) standards, the height of a panelboard's installation is essential for safety and accessibility. When the bottom of a 277/480-volt panel is at 38 inches above finished floor (AFF), it is important to ensure that the top of the panelboard remains accessible and complies with the height requirements specified by the NEC.

For a panelboard operating at these voltages, the NEC stipulates that the top of the panel should not exceed a certain height to maintain safe working conditions and ensure that it is within reach for servicing. The relevant NEC section that addresses panelboard installation indicates that the top of the panel should typically be no higher than 6 feet 7 inches (or 79 inches), and often there are additional considerations for the working space in front of electrical equipment.

Therefore, if the bottom of the panel is at 38 inches AFF, to ensure compliance with NEC standards concerning maximum height, the upper edge of the panel would reasonably be expected not to exceed approximately 7 feet 2 inches. This answer aligns with the safety and accessibility provisions that are designed to protect workers and ensure that electrical panels can be easily accessed for maintenance and operation.