There are a large number of electrical wires that travel throughout your house and they usually start their journey from the electrical box in your basement. The most common type of single conductor cable in your home is THHN and the most common type of cable is Romex NMB Cable. NMB is an indoor cable with multiple THHN cables inside for contractors to install multiple cables with one cable instead of running each one individually.

Romex is a brand of NMB cable so if you want to buy it from a vendor, you have to order the NMB cable, unless you specifically want the Romex brand. This will be the cheapest version of an indoor electrical cord you can find for a number of reasons.

The first reason for the lost cost approach of the NMB cable is that it is designed for indoor use only. An electrical cable with approvals for outdoor, conduit, or underground use will cost slightly more due to higher engineering and manufacturing costs. A cost-effective cable for electricians and contractors to use indoors is exactly what they need in most cases.

Most electrical cables are manufactured without much flexibility. By holding a Romex 6/3, it will be very difficult to fold or wrap around your wrist for a specific reason. The reason it isn’t flexible is because it can slide through interior walls and ducts much more easily. A flexible cable would bunch up and be a very difficult installation. As a cable becomes less flexible, it is cheaper to manufacture and easier for contractors to use, making it a win-win situation.

the last reason Romex NMB cable is less expensive This is due to the thin PVC sheath and uninsulated ground wire. Since it’s designed to be an indoor cable, there’s no need for a protective jacket, so instead, a thin, inexpensive PVC jacket to simply bundle the THHN cables together will work just fine. MC cable is an outdoor cable with an insulated ground wire instead of a bare copper ground. Removing the insulation from the ground will not cause any problems for an indoor application and will once again reduce the cost of the NMB cable for those installing it indoors only.

If you are looking for an indoor electrical cable, then the NMB cable is the way to go. Romex is an industry leading brand that you will find at most providers. Don’t worry, the brand name doesn’t add to the cost of the cable, or it would defeat the purpose of having an inexpensive indoor cable to work with.