306.6 Appliances Above Ceilings
Appliances that are located above the ceiling shall have ready access for inspection, service and repair without removing permanent construction. Appliances shall be provided with access to panel or removable ceiling tile with minimum nominal dimensions of 24 inches by 24 inches (609 mm by 609 mm).
The appliance is not required to be removable or replaceable through the access panel or removable ceiling tile. The appliance may be removed or replaced by removing the ceiling or wall assemblies adjacent to the appliance as long as they are not permanent construction.