In potentially damp locations, hangers or supports that are in contact with the tube shall be what or otherwise electrically insulated from the tube?

In potentially damp locations, it is essential that the hangers or supports in contact with the tube are plastic-coated or otherwise electrically insulated to prevent any electrical conduction that could lead to hazardous situations. Plastic coatings provide a reliable barrier to moisture and help prevent corrosion and deterioration of the metal components, which is critical in maintaining the integrity and safety of medical gas systems. The use of plastic-coated materials is particularly recommended because they ensure that there is no direct metal-to-metal contact, which could create a path for electrical current, thus avoiding the risk of electrical shorts or other hazards in environments where dampness is a concern.

The other methods, while they may provide some level of protection, do not offer the same consistent and effective insulation properties as a plastic coating, making this option the most suitable for addressing safety in potentially damp installations.