The thermoplastic high-heat resistant nylon-coated wire, or THHN wire for short, is a general purpose building wire designed for lighting and power circuits at 600 volts or less. The THHN wire differs slightly from the THWN wire, short for thermoplastic heat- and water-resistant nylon-coated wire, in that the latter comes with an outer sheath of PVC for added water resistance.

THWN Wire
Waterproofing is the major reason why cable buyers should prefer THWN wire over THHN version. In applications where a conduit is not available, the THWN wire provides all the features typically found in the THHN cable, all the while offering additional water resistance.

THHN Wire
THHN wire is typically two-conductor, and is widely used in homes and other structures to connect branch circuits and appliances.

Note that the difference between the two wire types is minor in most applications, so we've decided to make these into one type of product.

1. Scope
THWN or THHN wire is commonly seen in residential, commercial and industrial buildings. The electrical wire may be operated at the maximum continuous temperature of 90℃ in dry conditions and 75℃ in wet conditions and is listed by Underwriters Laboratories for use in accordance with Article 310 of the National Electrical Code. The THWN wire or THHN wire shall also be C (UL) listed as Types T90 Nylon or TWN75, FT1 indicating suitability for use in accordance with the Canadian Code.

2. Applicable Standards
The following standards form a part of this specification to the extent specified herein:
2.1.Underwriters Laboratories Standard 83 for Thermoplastic Insulated Wires .
2.2. Underwriters Laboratories Standard 1063 for Machine-Tool Wires and Cables (Stranded items only).
2.3. Underwriters Laboratories Standard 758 for 105℃ Appliance Wiring Materials (Stranded items only).
2.4. CSA Standard C22.2 No. 75 and Electrical Bulletin No. 1451 for Type T90 Nylon or TWN75.
2.5 Federal Specification J-C-30B.

3. Conductors
Conductors shall be solid, Class B or Class C stranded, annealed uncoated copper per UL Standards 83 or 1063.

4. Insulation
4.1. Each conductor shall be insulated with PVC and sheathed with nylon complying with requirements of UL Standard 83 for Types THHN or THWN , UL Standard 1063 for Type MTW and CSA C22 .2 No. 75 for T90 Nylon. In addition, Types THWN or THHN shall comply with the optional Gasoline and Oil Resistant II rating of UL Standard 83. The insulation on stranded sizes shall also comply with UL requirements for 105℃ Appliance Wiring Material.

4.2. The average thickness of PVC insulation, for a given conductor size, shall be as specified in UL Standard 83 for Types THWN or THHN. The minimum thickness at any point, of the PVC insulation, shall be not less than 90% of the specified average thickness. The minimum thickness at any point of the nylon sheath, shall be as specified in UL Standard 83 for Types THWN or THHN. The PVC insulation shall be applied tightly to the conductor and shall be free-stripping.

5. Identification
The THHN wire or THWN wire shall be identified by a surface marking indicating the manufacturer's identification, conductor size and metal, voltage rating, UL Symbol, type designations and optional ratings. The wire shall also be identified as C (UL) Type T90 Nylon or TWN75, FT1.

6. Tests
THHN wire or THWN wire shall be tested in accordance with the requirements of UL Standard 83 for Types THWN or THHN wire and for the optional Gasoline and Oil Resistant II listings; as Type MTW to UL Standard 1063 (stranded items); as AWM to UL Standard 758 (stranded items); and as C(UL) Type T90 Nylon orTWN75.

7. Labels
THHN wire or THWN wire shall bear the Underwriters Laboratories labels for Types THWN or THHN (solid conductors) and Type MTW (stranded conductors) and the C (UL) label for Types T90 Nylon or TWN75, FT1.

Main Export Markets
Eastern Europe, North America, Mid East/Africa, Central/South America, Asia, Western Europe, Australia.

The advantages of THHN, THWN wire
1. Our company has been a professional Chinese power cable supplier for over 18 years.
2. The quality of our products is guaranteed. They are all CCC and ISO certified
3. 10%~20% lower average price compared to competitors.
4. Our employees are all capable and professional.
5. We ship THHN wire as well as THWN wire worldwide.

Package
1. Packing length: 100 to 1,000m reeled in a carton drum
2. Outer packing: carton box, pull box, wooden case
3. Other packing requirement: according to clients' request