What is acceptable for use as a down conductor guard?

Using PVC conduit as a down conductor guard is acceptable because it provides a protective covering that is non-conductive, lightweight, and resistant to environmental factors such as moisture and UV radiation. The role of a down conductor guard is to protect the down conductor from physical damage and to minimize the risk of corrosion. PVC conduit effectively fulfills these requirements without introducing any additional electrical hazards or weaknesses.

In contrast, plastic tubing may not provide the same level of structural protection or durability as PVC conduit. Wooden casing can deteriorate over time due to moisture and pests, making it less reliable. Flexible metal conduit, while providing some protection, introduces concerns about conductivity, which could compromise the safety of the lightning protection system. Thus, PVC conduit is preferred for its balance of protection and safety in this application.