Generally speaking, UF-B is about 20 percent more expensive than NM-B. The difference in pricing between NM-B electrical wire and UF-B electrical wire happens to be drastic. When used as NM, UF-B has to comply with the standards found in NEC 2008 and NEC 2011 Article 334.
UF electrical wire is perfectly suitable for most NM-B applications, though it is unnecessary to use it because it is too expensive for indoor applications.
However, it is still not advised to use it outdoors unless unavoidable because weather damage is very much possible. In this case, it has to be placed in an electrical conduit or another necessary type of protection. Despite this, NM-B wire is sometimes allowed to leave the building for a short distance. Though UF and NM-B have many things in common, NM-B wire can quickly rot if mistakenly used outside because it does not have the extra-protection of UF-B. The most crucial difference between UF and NM-B is that the latter is prohibited for outdoor use. Each of the wires of UF-B is extra-sheathed individually. It is suitable for direct burial without an electrical conduit because of the durable rubber sheathing that protects it from damage during installation and maintenance. UF-B stands for "underground feeder cable." UF-B electrical cable is designed to bring power from indoor to outdoor constructions. The ground wire does not need insulating, and the strands are sheathed with paper wrappers. The outer PVC jacket of the NM-B electrical cable is tough and does not need extra protection. It can also be applied in switches, tile walls, and lighting. It is mostly used in devices characterized as damp or wet, such as washing machines and dishwashers. NM-B is a non-metallic electrical wire used in residential building wiring for various devices and outlets. The Definitions of NM-B Wire and UF-B Wire Did someone suggest that you could use one or the other for connecting indoors to outdoors? Continue reading if you wish to know whether it is the best option for you. NM-B electrical wire and UF-B electrical wire are an example of such false pairing. However, in some cases, the cables are compared falsely and are not that similar. If you ever shopped for an electrical cable without a specific type in mind, you know that some cables are interchangeable when it comes to particular applications.