When is it acceptable to use exposed cable in a lightning protection system?

Using exposed cable in a lightning protection system can be acceptable when it is fastened correctly. This ensures that the cables remain secure and stable in place, preventing any unintended movement or damage that could compromise the effectiveness of the lightning protection system. Furthermore, properly fastened cables reduce the risk of wear and tear from environmental factors, such as wind or physical contact, which is vital in maintaining the integrity of the installation.

Correct fastening also helps to ensure that the exposed cable is not easily accessible, minimizing the risk of accidental contacts and potential hazards. Adequate fastening can contribute to overall system reliability by providing a clear path for lightning energy to follow, which is essential for ensuring safe and effective lightning dissipation.

While painting exposed cables (as mentioned in other options) might offer limited protection against environmental factors, it does not replace the necessity for proper fastening to meet safety and performance standards. The conditions for outdoor installations and specific limitations about exposure are also secondary considerations; the primary focus is on the secure installation of the cables to ensure complete system functionality.