What is the primary purpose of using NM (non-metallic) cable in residential applications?

The primary purpose of using NM (non-metallic) cable in residential applications is indeed to reduce installation costs. NM cable is lighter and easier to handle compared to metal conduit systems, which makes it simpler and more cost-effective to install. This type of cable does not require additional protective conduit in many situations, thus saving on material costs and labor time during installation.

Moreover, NM cable is typically less expensive than alternatives like armored cable or conduit systems, making it an attractive option for residential wiring. The flexibility and ease of use further contribute to lower overall project costs, allowing electricians to complete jobs more efficiently.

While some of the other options may seem relevant in different contexts, they do not capture the primary intent behind the widespread use of NM cable in the residential setting. For example, NM cable does not specifically enhance fire resistance, improve voltage ratings, or serve primarily aesthetic purposes in the way that it's commonly understood. Its cost-effectiveness and efficiency are the standout features that make NM cable a go-to choice for wiring in homes.