The key difference is the additional protections provided by the insulation of XHHW-2, which is a thermoset while THHN is a thermoplastic. The jacket of XHHW-2 wire is thicker and more rugged than THHN’s, provides more protection against chemicals, abrasion, moisture, and is more flexible as well. These additional benefits account for its higher price than THHN.

For example, XHHW-2 wire is hospital grade and has significantly higher insulation resistance than THHN. Though its jacket is actually thicker than THHN’s, XHHW-2’s thermoset material gives it greater flexibility. Furthermore, given its greater flexibility, it is often used in projects where there are lots of corners and bends. XHHW-2 is also rated for wet locations whereas standard THHN is not.

XHHW-2 wire’s benefits (which stem from its thermoset qualities) also account for why it is more expensive than THHN. The latter’s thermoplastic base is less expensive. However, along with its water-resistant insulation, XHHW-2 has a 90° C temperature rating in dry and wet locations. Kris-Tech goes beyond the standard requirements, offering a 105° C dry and 1000 volt rating.

Here are some common uses found for XHHW-2:

Often used as building wire XHHW-2 can be used in power circuits run in conduit from the utility meter to main circuit protection panels. It can also be used in conduit from circuit protection panels to uses throughout a building. Some other uses are machine tool wiring, appliance and control circuits.

Though it is pricier than THHN, XHHW-2’s additional benefits make it a popular choice for electrical contractors and electricians looking for a hardy wire product suited for industrial, residential, and commercial construction.