What type of wiring is specifically mentioned in Article 399?

Article 399 of the National Electrical Code (NEC) specifically addresses the regulations and requirements for outdoor overhead conductors. This includes conductors that operate above 1000 volts, which are subject to stringent safety standards due to the higher risks associated with higher voltage levels. The article outlines the appropriate materials, installation methods, and safety practices needed to ensure that these types of wiring are handled correctly to prevent hazards.

Understanding the specifics of Article 399 is crucial for electricians, especially when dealing with installations that require adherence to code for safety and compliance. High-voltage outdoor conductors have unique considerations, including clearances, attachment methods, and protective measures required by the NEC in order to ensure public safety and system reliability.