cutting white copper wires
Sep 26, 2023

What Is XHHW Wire?

Each letter in the acronym for XHHW refers to a different component of its construction:

X: The X refers to cross-linked polyethylene (XLPE) insulation. It provides much of the wire’s toughness and durability, even in very low or high temperatures.
HH: High heat resistance is important in many different environments. XHHW-2, the modern version of XHHW, has an operating temperature of up to 90℃ or 194°F in both dry and wet environments.
W: Similarly, water resistance is critical for many outdoor applications, meaning this wire can offer high performance in wet or humid locations.

We carry this single-insulated wire with a copper conductor in stranded configurations, though it’s also possible to find it with solid copper or tinned and annealed copper. It supports up to 600 volts and is available in American Wire Gauge (AWG) sizes 4/0 to 14 and circular mils (MCM) of up to 1,000.

XHHW wire also offers resistance to a wide range of damaging agents, including:

  • Heat.
  • Chemicals.
  • Oil.
  • Moisture.
  • Flame.
  • Sunlight.

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What’s the Difference Between XHHW and XHHW-2?

XHHW was the first version of this wire, followed by the modern XHHW-2, which improved the insulation properties for better moisture resistance. You’d be hard-pressed to find the original XHHW wire in present-day manufacturing practices.

XHHW-2 offers 90℃ performance in both dry and wet environments, but XHHW ‘s performance in wet environments is only 75℃, or 167°F.


With such wide-reaching applications, it’s no wonder you’ll find many different organizations weighing in on copper XHHW wire. Various groups and directives have given XHHW their seal of approval, including:

  • UL LLC.
  • The Institute of Electrical and Electronics Engineers (IEEE).
  • United States federal specifications.
  • ASTM International.
  • The National Electrical Manufacturers Association (NEMA).
  • The National Fire Protection Association (NFPA).
  • Restriction of Hazardous Substances (RoHS).
  • Registration, Evaluation, Authorization and Restriction of Chemicals (REACH).

If your project needs to abide by these organizations’ rules, or you want added trustworthiness, make sure your copper XHHW is listed with the right approvals. You can find these listed on our product pages for each wire.

What Is XHHW Wire Used For?

XHHW wire is valuable to many applications. Its build is perfect for industrial lighting and power, and it can be used in conduit, ducts and different approved raceways. You might find it in raceways for services, feeders and branch-circuit wiring. It can be used for many purposes, though it’s perhaps most common in industrial or commercial locations requiring toughness and resistance to moisture and heat.

One specialty of XHHW-2 is its ability to suit environments where the dielectric constant must be below 3.5. Places like healthcare facilities can take advantage of this characteristic.

Can You Direct Bury XHHW Wire?

In short, no, you cannot directly bury XHHW-2 wire, though you may find it used in underground conduit or raceways.


When looking for XHHW wire, you might also come across THHN, which refers to thermoplastic, high-heat and nylon-coated wire. This type of wire has thinner insulation made of polyvinyl chloride (PVC). It isn’t as strong or as flexible as XHHW, and it doesn’t perform as well in terms of chemical resistance. It also can release toxic substances during fires, so it isn’t as safe to use. XHHW also offers more resistance to ozone and abrasion and less signal leakage.

THHN or THHN-2 is cheaper and offers the same temperature tolerance as XHHW, but the characteristics outlined above often make XHHW the better choice in demanding or harsh environments. If that’s not a concern and regulations don’t require it, then THHN can be a more budget-friendly option.

Copper XHHW Wire From WesBell Electronics

We carry XHHW electrical wire in our New Hampshire warehouse and can rapidly deliver throughout the USA thanks to our manufacturer’s stocking locations. We can drop ship our XHHW-2, as well as our THHN-2 wire when necessary. If XHHW seems like more than you need, check out our THHN wire, which is slightly less expensive because it doesn’t hold the “sunlight-resistant” approval or as much durability as XHHW.

No matter which cable you need, you’ll get plenty of support from the experts at WesBell Electronics. We can help you identify the right cable for your application and even provide preparation services so your cable or wire reaches you ready for the job.

Contact us if you have any questions!

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