MC and UFB are both types of 12-2 electrical cable Used in the home and building construction industry. They help distribute power throughout the home from the electrical box to power, lighting, control, and signal circuits. MC stands for Metal Clad and UFB stands for Underground Feeder and there are only a few slight differences between the two.
First, MC 12-2 cable is used in a few different specific applications. It was designed as an indoor cable used to make a connection without the use of conduit.. Standard indoor NMB cable should be used inside conduit for indoor applications, while MC cable has a metal clad jacket that also serves as conduit. That saves time during the installation process and is worth the slightly higher price compared to the NMB cable.
The second application is outdoors and in duct.. Romex® NMB cable is only approved for indoor applications, so you will need to upgrade to MC cable for outdoor and underground conduit applications. The extra ground wire has THHN THWN approved green insulation along with the rest of the conductors, which means they can be used outdoors and in conduit. Aluminum interlock armor is the description of the metal clad jacket that is wrapped around the conductors.
UFB cable is designed to be used directly underground without conduit or raceways. It has a very strong PVC jacket that covers each of the conductors individually for added protection. It is even a bare copper ground wire on uninsulated UFB cables that is fully protected by the rugged outer jacket. The price of each cable is in order of environment, considering that the NMB cable is the cheapest, then the MC cable and finally the UFB cable is the most expensive.
Each type of electrical cable is manufactured for a specific application that will be in a specific environment. They know where the MC 12-2 cable will be used and design the approvals based on what is needed. For example, an indoor cable will not need to resist moisture or gases, but an outdoor cable will. More expensive cables require more engineering and more difficult manufacturing procedures, making them more expensive.
Talk to your wire and cable supplier about the type of 12-2 electrical wire you need. You don’t want to spend too much buying underground cable for an indoor application, so having a bit of knowledge before you buy will prove helpful.
