Which of the following statements is true regarding liquidtight conduit fittings?

The statement that liquidtight conduit fittings should be listed is accurate because listing indicates that the fittings have been tested and meet specific safety and performance criteria established by a recognized testing laboratory. Using listed products ensures compliance with relevant codes and standards which is essential for ensuring the safety and regulatory adherence of electrical installations.

In the context of electrical installations, particularly where moisture and environmental conditions might affect the integrity of the wiring, using listed liquidtight conduit fittings helps to guarantee that the installation will function reliably and withstand adverse conditions. This is especially important in commercial and industrial applications, although it can also be relevant in residential settings.

While liquidtight conduit fittings may be made from various materials, it is not a requirement that they must be metal, nor are they always necessary in every wiring scenario. The option stating that they are optional suggests they may not be needed in all cases, which is not true as proper fittings are crucial for the safety of installations exposed to liquid or moisture. Thus, the necessity for fittings to be listed emphasizes the commitment to safety and compliance within electric conduit systems.