MC and UFB are both types of 12-2 electrical wire used in the building industry for homes and buildings. 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 cable 12-2 is used in a few different specific applications. It was engineered as an indoor cable used to make a connection without the use of conduit. Standard indoor NMB cable needs to be used inside of conduit for indoor applications while MC cable has the metal clad jacket which also provides as conduit. So that saves time during the installation process and it’s worth the slightly higher price compared to NMB cable.
The second application is outdoors and in conduit. Romex® NMB cable is only approved for applications indoors so you’ll need to upgrade to MC cable for outdoor and underground conduit applications. The additional ground wire has a green insulation approved as THHN THWN along with the rest of the conductors which means they can be used outdoors and in conduit. The aluminum interlocked armor is the description for the metal clad jacket which is wrapped around the conductors.
UFB cable is engineered to be used directly underground without conduit or raceway. It has a very strong PVC jacket that covers each of the conductors individually for added protection. They is even a bare copper ground wire in UFB cables without insulation which is fully protected by the strong outer jacket. The pricing of each cable goes in order of environment deeming NMB cable the cheapest, then MC cable and finally 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 MC cable 12-2 will be used and engineer the approvals based on what is needed. For instance, an indoor cable will have no need to resist moisture or gasses but an outdoor cable will. More expensive cables need more engineering and more difficult manufacturing procedures which make it more expensive.
Speak to your wire and cable supplier about the type of 12-2 electrical wire you need. You don’t want to over spend by getting an underground cable for an indoor application so having a bit of knowledge before buying it will prove to be helpful.
