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NEC, THHN & AWG Wire Gauge Ampacity Rating Chart

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June 10, 2024

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If you have been to an electrical store, you will notice electrical wires come in several sizes. Most people would think that it does not matter and is pure aesthetics.

Its size greatly depends on other things, such as the electrical current passing through. We will be going through the different products in the following sections using the American wire gauge system.

Summary

The NEC, THHN, & AWG wire gauge amp chart is the easiest way to see the amp rating for different wire thicknesses. From it, you can see a list of things, including:

• The 6 gauge wire amp rating is 65 amps for copper, with 167°F ambient temperature.
• The 4 gauge wire amp rating is 85 amps for copper, with 167°F ambient temperature.
• The 2 gauge wire amp rating is 115 amps for copper, with 167°F ambient temperature.

Table of Contents

• NEC, THHN & AWG Wire Gauge Ampacity Rating Chart
• THHN vs. THWN
• How to choose the right one?
• Wires sizes

NEC, THHN & AWG Wire Gauge Ampacity Rating Chart

This section only serves as a guide when looking at a gauge chart. If you plan to install anything involving electricity, always call for a professional electrician to handle the work for you.

The table below shows that the AWG value is opposite the diameter. It means a higher AWG value would mean a smaller size. For example, a 12-gauge option can carry a higher amp than an 18-rated one.

THHN vs. THWN

When looking at electrical wires, manufacturers use different types of material for the coating. The most common types are the Thermoplastic High-Heat Nylon-coated (THHN) and THWN. It stands for “Thermoplastic Heat and Water-resistant Nylon-coated.” Suppose you think about how these two are different.

The THWN can operate in an environment similar to the THHN without additional accessories. The Thermoplastic Heat and Water-Resistant Nylon-coated wire is a better version of the THHN. You can still find both across different infrastructures.

Thermoplastic High-Heat Nylon-coated (THHN)

The Thermoplastic High-Heat Nylon-coated wire is probably the more common option between the two. You can find this product in almost any commercial or residential building. Depending on the size, it comes in either a stranded or a solid wire. It uses either aluminum or copper as the conductive material.

Finally, polyvinyl chloride (PVC) wraps the conductive material and serves as insulation. THHN rates at 75°C in a wet location or 90°C in a dry location. Several options of this type carry a dual rating cable, which you can identify by a THHN / THWN marking.

If you think about distinguishing this from other types, you will observe its PVC insulation. In most cases, it uses a thinner one. It is important in electrical properties to determine its amp rating.

A negative effect of having a thin insulation layer is frequent current leaking, leading to a breakdown. When the insulation in THHN burns, it releases toxic smoke. It is highly undesirable.

Since this type uses nylon coating, it is not extremely flexible. It becomes an issue for some people, especially those who want to maximize saving time and energy during installation. Despite its cons, the THHN is still very popular because it is cheaper.

When you plan to wire an entire building, you will want to save money whenever you can. Having a cost-effective solution without sacrificing safety goes a long way, so several people still go for a THHN.

Thermoplastic Heat and Water-resistant Nylon-coated (THWN)

Thermoplastic Heat and Water-resistant Nylon-coated (THWN) are the least common of the two. According to the National Electrical Code, you can mostly find this type in industrial and commercial buildings. Its outer layer is tough yet easy to pull and bend.

When installing it, electricians will not have a hard time bending it. It saves them time and energy in the long run. The THWN is also resistant to common chemicals, such as gasoline and moisture.

Unlike THHN, you can commonly find the THWN in alternating current electrical distribution systems across the country.

It can be used during the installation of a range of things, including:

• Machine tools
• conduits
• feeders
• controlled circuits.

These systems typically have voltage levels that range from 110 volts to 600 volts. It uses copper or aluminum conductors, either solid or stranded.

It is suitable for use up to 90°C temperature in dry and wet locations. When it comes in contact with oil or coolant, the suitable temperature you can expose it to decreases to 75°C.

The THWN wire has approvals from several laboratories and regulatory boards, including:

• The Canadian Standards Association
• Underwriters Laboratories
• American Society for Testing
• Materials Miscellaneous
• Restriction of Hazardous Substances Directive

Is it dangerous to use the wrong one?

The short answer to this question is yes. It is dangerous to use an incorrect size. If you want to avoid unnecessary danger if you’re welding, you’ll want to make the right electrical choices.

A common misconception is that there won’t be any issues as long as the wire fits with the connector. When dealing with circuit breakers, pay much attention to the wire.

Those unaware often use an AWG below the recommended rating because it is cheaper. They think it won’t make any difference. In the long run, getting a smaller one than what you should be getting will only cost you more.

Professional electricians often recommend using a larger rating for your circuit breaker. You will greatly reduce the chances of using the incorrect option. You don’t want to pick one that can’t handle the necessary amount of amps you’re dealing with.

Picking a bigger one will not negatively impact performance or safety. The only negative effect it has is on your budget, which will cost you more than using a substandard option. Looking at it in the long run, you can save more because you will unlikely run into damage with your circuit breaker.

How to choose the right one?

It is important to know about compatibility across different scenarios when dealing with electrical components. Choosing an incorrect size could lead to burning or fire at worst. People think it does not play an important role, but it does. Pick the correct one to prevent any accidents from happening.

When dealing with a circuit breaker setup, extra precautions need to be in place. For example, the AWG needs to be compatible with the circuit breaker you plan to use. One that is too small for the circuit breaker could lead to a drop in performance. At worst, it can start a fire.

In the following sections of this article, we will discuss the maximum amps a particular AWG can support. If you have an 8-gauge, will a 30 amp circuit breaker work with it without any issues?

Wires sizes

Whether you’re looking for the ampacity for AWG wire 6 through 26, you can find it in the section below. All the corresponding numbers refer to the gauge.

0 (1/0)

There is a general rule of thumb when choosing an AWG wire. You need one that can handle your amp requirements. It can handle any amount of amperes below its maximum capacity.

The maximum amperes it can handle for the 0 (1/0) gauge is 150 amps. It means it can handle any amount of amps as long as it is below its maximum capacity. Typically, you can use it as a cable for your car audio.

2/0

You can use a 2/0-gauge copper wire for a maximum of 190 amperes. It can handle anything below its maximum capacity without any issues. If you own a sailboat that operates with a battery, you can replace any wire connecting to the battery. 

3/0

A 3/0-gauge supports a maximum amperage capacity of 239 amps and can handle anything below its maximum capacity. A 3/0 is perfect for a portable solar setup, allowing you to get the most amps. 

1

If you have a 1-gauge product, it supports a maximum of 119 amps. Any device that needs 119 amps of current or below will work fine with this type of product. 

2

A 2-gauge wire supports a maximum capacity of 94 amps, which means it will work fine for any device that needs less. It is good to use this for relocating your car battery. You can also use it to install amplifiers and high-powered car subwoofers in your vehicle.

TEMCo

Here’s a 2-gauge wire and the best place to get it.

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3

You can use a 3 gauge for a maximum of 75 amps. It can also support any device below 75 amperes. It is good to use this in your main panel or subpanel at home. Be sure your electrical system at home has a ground wire. Hence, excess electrical charges have a safe place to travel in case. 

4

A 4-gauge wire is otherwise known as the 4 AWG. It supports a maximum amperage capacity of 60. This has a wide range of applications. You can use it for your audio devices, such as a subwoofer or amplifier. It’s also great for off-grid systems, such as solar panel systems or welding applications. 

[amazon box=”B00LIB7YTU” title=”TEMCo Industrial ” description=”Here’s another product from TEMCo.”]

6

If you have a 6-gauge wire, it can support a maximum of 37 amperes. It can also support any device that needs less than 37 amps. It is good to use with almost anything that involves automotive.

If you plan to use this in an automotive, be sure to consider motor vibration. Over time, it could cause it to break. Be sure to provide enough isolation and strain relief.

8

An 8-gauge, also called 8 AWG wire, supports a maximum amperage capacity of up to 24 amps. This is good to use with some of the following:

• batteries
• lamps
• household appliances
• meters
• model cars
• planes
• and electric heating appliances.

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9

If you have a 9 gauge, it can support a maximum of 19 amperes. It is ideal to use this for a 4-channel amplifier for speaker installation. 

It can be used for a:

• RV air conditioner
• Washer
• Dryer

10

A 10 gauge can support a maximum of 15 amps. This is useful for a range of household appliances. It can also be used for electric heating appliances and lamps.

It is enough to power:

• A water heater
• A furnace fan
• A space heater
• A microwave oven

12

If you have a 12-gauge, it can support a maximum amperage capacity of 9.3 amps. You can usually use this in connecting an amplifier with a subwoofer. Certain things like lawnmowers and leaf blowers may also use this type, assuming they are corded rather than using gas.

It’s enough to power a:

• crock-pot
• Furnace fan
• Food processor

14

A 14-gauge supports a maximum ampacity of 5.9 amps. It also supports anything below 5.9 amps. It is good to use it for your car audio system or home theater system.

16

A 16-gauge supports a maximum of 3.7 amperes and can handle any device below it. Typically, you can find this amount of current in aluminum batteries or RC batteries. It’s also what is used in LED lighting. 

18

You can use an 18-gauge wire with any device that needs 2.3 amperes or less.

Uses:

• Oscillating fan
• Light bulb
• Crock-pot
• Curling iron

20

A 20-gauge supports a maximum ampacity of 1.5 amps, which means it can handle any device that requires less than 1.5 amps. You can widely use this in RC batteries or LED lighting.

22

A 22-gauge can handle a maximum of 0.92 amps. It is good to use it in RC and LED lighting. 

24

If you have a 24-gauge, it can handle a maximum of 0.577 amps.

26

A 26-gauge can handle a maximum of 0.361 amps. In most cases, you can use this for gate openers. However, be sure to check the current requirements before getting one.

28

A 28-gauge can handle a maximum ampacity of 0.226 amps, which means it can handle any device with a smaller amps requirement. This is good to use with aluminum batteries and LED lighting at home.

Make sure also to check out this post that has the NEC table. We also have various articles on ThermoKing fault codes and welding joints.

We have written extensively on the topic of electrical safety because it is potentially something that could harm your family. You may be standing at Home Depot thinking, wanting to buy the cheapest option available.

You should know that it may not be the best decision. On top of that, using an extension cord that’s not rated for your intended use could void the warranty of your expensive tools!

Uses:

• Jewelry

If you’re renovating or building a new home, you’ll need to know your electric game well. In this case, you should know the right wire size for each job on the project. We give you some tips below.