What is THWN?

THWN wire refers to a specific type of insulation material, temperature rating, and condition of use for electrical wire and cable. It is the most common type of electrical wire due to its use as a single conductor wire while also being used in most electrical cables. The conductors are used in commercial and industrial applications specified in the National Electrical Code. 


What Does THWN Mean?

The meaning of THWN is “Thermoplastic Heat and Water-resistant Nylon-coated.” It’s tough outer jacket provides easy pulling, and the wire is resistant to chemicals like gasoline and oils, moisture, and flames. 


Where Can I Shop for THWN Cable?

You can conduct all your shopping for wires and cables through Nassau Electrical. We have competitive prices and offer instant quotes for your satisfaction. You’ll be able to purchase the required length for your application, and our prices are per foot of wire.  

View our selection of THWN wire by clicking here.


Applications

THWN wire is often used in alternating current electrical distribution systems of many different types of buildings in North America. This is usually at voltage levels of 110-600 volts. Aluminum and copper conductors, sold as stranded or solid, use THWN insulation. The wire is typically used for installation in conduit, machine tools, controlled circuits, or other general purpose wiring. 


Specifications

There are many wires that are rated THHN as well as THWN, and these are usually suitable for use in dry locations up to 90° C or wet locations up to 75° C, depending on which you use. With THHN, the conductor is suitable for use in dry locations up to 90° C. With THWN-2, the conductor is suitable for use in wet or dry locations with temperatures up to 90° C, but 75° C if exposed to oil or coolant.


What Are Specific Examples of THWN Cable?

View some of our THHN/THWN products by clicking any of the links below. Nassau Electrical carries a wide selection of THWN wire to meet your specifications. We have gauges that range from six to 14, and each product has 19 strands. The sizes we offer are suitable for appliance wiring material up to 105°C. Browse from our available products and let us know if you have any questions. We strive to provide you with the best possible experience, and will provide answers to any inquiries regarding specific wiring and cable materials. 


The THWN Cable

The Thermoplastic Heat and Water-resistant Nylon-coated (THWN) cable is used primarily in cable and conduit trays for branch circuits, feeders and services. It is an ideal cable for environments that are usually moist because its performance is not altered by the moisture. The THWN cable can withstand temperatures of up to 90°C in both dry and wet environments. When the wire is exposed to coolant or oil, it should not be operated in areas with temperatures above 75°C.

In addition to being water resistant, the THWN cable is also heat, gasoline and oil resistant. Its thermoplastic and nylon sheath insulation makes it a suitable cable for use in environments where oil and gasoline are common features. The THWN is an ideal wire for power distribution. It has a voltage rating of 600 volts. It has a low friction coefficient, is abrasion resistant and retardant to sunlight.

The THWN cable has attained approval by the Underwriters Laboratories (UL). It also meets the standards set by the Canadian Standards Association. The wire complies with the Restriction of Hazardous Substances (RoHS) as well as the American Society for Testing and Materials Miscellaneous (ASTM). It also meets the requirements set by the National Electrical Code.

Some of the variants of the THWN cable include;

  • AL-THHN-8 size 8 AWG with a stranding of 7, a conductor diameter of 0.134, an insulation thickness of 0.045inches, a jacket thickness of 0.005 and an ampacity of 45 at 90°C
  • AL-THHN-6 size 6 AWG with a stranding of 7, a conductor diameter of 0.169, an insulation thickness of 0.045 inches, a jacket thickness of 0.005 and an ampacity of 60 at 90°C
  • AL-THHN-4 size 4 AWG with a stranding of 7, a conductor diameter of 0.213, an insulation thickness of 0.045 inches, a jacket thickness of 0.006 and an ampacity of 75 at 90°C
  • AL-THHN-2 size 2 AWG with a stranding of 7, a conductor diameter of 0.268, an insulation thickness of 0.045 inches, a jacket thickness of 0.006 and an ampacity of 100 at 90°C
  • AL-THHN-1 size 1 AWG with a stranding of 18, a conductor diameter of 0.299, an insulation thickness of 0.55 inches, a jacket thickness of 0.007 and an ampacity of 115 at 90°C

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