Which type of wiring must be installed in metal raceways or specific cable types in aircraft hangars?

In aircraft hangars, the installation of wiring is subject to specific regulations and safety standards due to the unique hazards present in these environments. Type TC (Tray Cable) is specifically designed for use in industrial applications, including aircraft hangars, where additional protection and flexibility are necessary. This type of cable can be installed in metal raceways, which provide enhanced protection against physical damage and ensure that wiring is safely organized.

Type NM (Non-Metallic Sheathed Cable) and Type UF (Underground Feeder) are not suitable for aircraft hangars, as they do not meet the required standards for protection and installation in such potentially hazardous locations. Type NM is generally not intended for use in wet or damp locations, and Type UF, while designed for underground applications, lacks the robustness needed in an aircraft hangar setting. Thus, Type TC is the preferred wiring for these environments.