About THHN Wire
THHN wire is the most common type of single conductor electrical wire used in the industry. The THHN acronym stands for thermoplastic, high-heat and nylon, and it refers to some of the characteristics and components that make up the wire’s jacket and insulation. Thanks to its characteristics and capabilities, THHN-2 wire has earned itself a position as one of the most common building wires used that can pass most building codes.
Let’s take a closer look at THHN wire. We’ll review what it does, where it’s used and some of the different types you might see.
What Is THHN Wire?
THHN wire can come in a wide range of configurations, but at the heart of it all, you’ll find several benefits associated with each part of the acronym:
- Thermoplastic: Thermoplastic insulation includes materials like polyvinyl chloride (PVC) and polyethylene (PE). They are easy to work with and can be stripped if needed, offer a range of performance characteristics and provide easy identification through different colors.
- High-heat resistance: These wires are rated for up to 194°F or 90℃, providing plenty of room for use in most buildings.
- Nylon coating: The nylon jacket around the wire protects it from abrasion and cuts, as well as various destructive agents like oil, chemicals and water.
You may also hear the terms THWN, THWN-2 and THW in reference to this material, which we cover further on in this guide.
Does THHN Wire come in different colors?
Yes, THHN wire comes in a standard 10 colors including black, brown, blue, gray, green, orange, red, violet, white, and yellow. You might find THHN wire in pink, as well, but it’s less common. You can also stripe THHN if you need another color option. Typically, the green wire is made green with a yellow stripe, but you can use your imagination.
Does electrical wire come without the nylon coating on the wire?
Yes, you can get something called THW wire, which simply removes the “N” that stands for “nylon.” It can be hard to find THW because there aren’t many manufacturers that stock this wire. One option is to use hook-up wire instead, but keep in mind that it will be much more flexible than electrical wire.
Hook-up wire can come in bare copper instead of the usual tinned copper, and the smaller American Wire Gauge (AWG) sizes can come in a solid version. However, the bigger AWG sizes will be much more flexible than the standard electrical wire, so you’ll need to be careful or it might get bunched into the conduit. If you need a nylon-free wire, you can always reach out to us and we’ll help you determine the most effective solution.
What’s the difference between Romex® and UFB cable?
Romex® and UFB cables are both made with THHN wires on the inside of the cable and provide the exact same function. However, Romex® wire was made to be an indoor cable with a cheap outer jacket to make it more affordable for electrical contractors.
The UFB cable is an underground cable used outdoors because of its tough outer jacket. The “B” in UFB stands for ground wire. Most UFB cables come with a ground wire anyway, because it’s usually needed for the job.
Copper THHN Wire
Copper THHN wire is a common type of single-conductor building wire used in homes and buildings to run power to outlets and lights. Copper wire is first connected to the electrical box in the basement, then it travels through the walls to each outlet, providing power to small appliances, electrical equipment and anything else you may need to plug in.
There are a few different sizes that typically offer different functions.
THHN 10, 12 and 14 AWG
These sizes are known as circuit-size electrical wiring. They’re most commonly seen as the wires inside of Romex® cable. Romex® bundles three wires together and wraps them in a PVC jacket so the electrician can run all three wires at once instead of one at a time. We offer THHN 10 AWG, THHN 12 AWG and THHN 14 AWG in small-quantity spools of 100, 500 and 1000 feet.
THHN 8, 6, 4 and 2 AWG
Moving up in size, you’ll need to use these cables when the application calls for more power. The larger sizes are hooked up to things like a stove, dryer or hot tub. These also come in a Romex® cable, which you may know as Romex® 6/3 cable. That means all of the wires inside are 6 AWG and there are three conductors. You’ll often find an additional bare copper ground wire included inside the PVC jacket.
THHN 1/0 and Larger
Any larger types of copper THHN wire are labeled 1/0, 2/0, 250 thousands of circular mils (MCM) and so on. These very large electrical cables bring power to an electrical box from the street.
As an example of how these wires work together, a THHN 4/0 cable can bring 1,000 Amps to the electrical box in your basement, allowing smaller wires to pull 10 Amps to each outlet, 30 Amps to the stove, 40 Amps to the hot tub and so on. Once your electrical box reaches the maximum, an additional wire will need to connect to the box from the street.
THHN Wire From WesBell Electronics
Here at WesBell Electronics, we carry a wide range of THHN-2 cables, all rated for the capabilities of THHN, THW and THWN. We carry many different AWG sizes for any application, and our THHN electrical wire prices are particularly cost-effective. Our wide range of services can also help you get cables ready for installation without any prep work.
If you’re not sure what you need or are looking for more information on THHN wire, reach out to us today! We’re happy to go over your application with you and help determine the right cable for the job.