What type of wiring is discussed in Article 394?

Article 394 of the National Electrical Code (NEC) specifically deals with "Messenger-Supported Wiring." This type of wiring is typically used in outdoor or other environments where traditional installation methods may not be adequate. It utilizes a messenger wire, which is a support line suspended between poles or structures, and electrical conductors are attached to this support, facilitating the installation of wiring in locations that may be challenging to reach otherwise.

The focus of Article 394 is on the requirements and guidelines related to the safety, installation methods, and protection processes of messenger-supported systems. Understanding this article is crucial for ensuring compliance with safety standards when using this type of wiring, as it outlines specifications to reduce risks associated with environmental factors and mechanical stresses.

In contrast, the other options refer to different wiring types that are addressed in other articles of the NEC. Knob-and-tube wiring has historical significance but is not the focus of Article 394, nor are fixture wires or flexible cords, which are categorized under different provisions and guidelines within the NEC.