What does Thhn wire mean?
Christopher Harper
Updated on April 04, 2026
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Then, what is the difference between Thhn and THWN wire?
THHN is a code for thermoplastic high heat resistant nylon coated wire which is allowed for use in dry to damp location and rated for a maximum temperature of 90ºC (194ºF). The THWN wire we carry is actually coded THWN-2 indicating its rated 90 degrees for both wet or dry locations which is even better.
Also, where is Thhn wire used? THHN or Thermoplastic High Heat-resistant nylon is a wire coated in plastic and runs through conduits. It is used for general building purposes such as residential and commercial wiring. The National Electric Code recommends and allows it to be used in dry locations only.
Likewise, people ask, what does THWN mean?
THHN stands for Thermoplastic High Heat-Resistant Nylon and THWN stands for Thermoplastic Heat and Water-resistant Nylon. Thermoplastic is a type of PVC material that is thinner than other types, making it lightweight.
Is Thhn wire water resistant?
Thermoplastic, high heat, Nylon coated. THHN wire without a dual approval of THWN is not water resistant. The added "W" stands for water resistant so that it could be installed outdoors and in conduit when THHN wire could not. However, again, remember that they're all combined into a universal wire now.
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