How often should intermediate metal conduit be marked with the letters IMC?

Intermediate metal conduit (IMC) must be marked with the letters 'IMC' at specific intervals to ensure that it is easily identifiable during installation and maintenance. The correct marking interval is every 5 feet. This regulation is designed to enhance visibility and recognition, ensuring that workers can promptly identify the type of conduit being used, which is crucial for safety and compliance with electrical codes.

Marking every 5 feet helps maintain a consistent identification method, allowing for efficient inspection and facilitating the proper handling of the conduit. Additionally, this requirement supports best practices in electrical installations, ultimately helping to minimize confusion about the materials being employed in a structure.

Intervals that are too short, such as marking every 2 feet, could lead to unnecessary clutter and could complicate the task of identifying other types of conduits or equipment nearby. On the other hand, marking at longer intervals, like every 10 or 15 feet, may result in missed identification, especially in larger installations where distances can be significant between markings.