NCIDQ IDFX Practice Exam

Which cable is noted for being moisture-resistant and suitable for residential buildings?

1. BX or flex cable

2. Romex

3. Individual plastic-insulated conductors

4. Metal conduit

The correct answer is: Romex

Romex, also known as NM (non-metallic) cable, is specifically designed for residential wiring and is widely recognized for its moisture-resistant properties. The sheathing on Romex consists of a durable plastic material that helps protect the conductors inside from moisture, making it suitable for residential buildings where exposure to humidity or occasional dampness may occur. This allows it to be installed in various areas of a home, including basements and areas that might require some degree of moisture protection. In contrast, other options may not have the same level of moisture resistance or suitability for residential environments. BX or flex cable, for example, may be used in some residential settings but typically offers less moisture resistance due to its metal sheath and cable construction. Individual plastic-insulated conductors lack the protective outer jacket that Romex provides, making them less suitable for use in areas where moisture is a concern unless they are properly encased. Metal conduit is often used for exposure to mechanical damage rather than moisture resistance and is typically seen more in commercial settings rather than residential applications.