Most building wire, such as THHN and XHHW, are Class ? stranding.

The correct answer is B, as most building wire types, including THHN (Thermoplastic High Heat-resistant Nylon-coated) and XHHW (Cross-Linked High Heat-resistant Water-resistant), utilize Class B stranding.

Class B stranding consists of 7 strands; specifically, these strands are typically made up of smaller wires grouped together to form a larger conductor. This configuration provides greater flexibility compared to Class A stranding, which employs a single solid wire or fewer strands. The flexibility of Class B stranding makes it particularly suitable for applications where the wire needs to be maneuvered around corners or fitted into conduits in tight spaces.

In this context, the properties of Class B stranding enable the wires to withstand handling, installation, and the dynamic movements they may encounter throughout their service life. Understanding this classification helps electricians and those in the electrical field to choose the right type of wire for various building and construction applications.