Each disconnecting means must be legibly marked to indicate its purpose unless:

The requirement that each disconnecting means must be legibly marked to indicate its purpose is essential for ensuring safe operation and maintenance of electrical systems. However, if the purpose of the disconnect is evident through its design or location, marking may not be necessary. For instance, if a disconnect switch is clearly labeled based on its proximity to specific equipment or is a standard design convention widely recognized in the industry, this could render an explicit label redundant.

This provision in the National Electrical Code promotes clarity and safety while allowing for practical flexibility, acknowledging that sometimes the function can be inherently understood without additional markings. Ensuring that operators and maintenance personnel recognize the purpose of disconnecting means at a glance helps prevent accidents and enhances the overall safety of electrical installations.