20AWG wire is relatively common. But some people rarely use it because it is low voltage. You are unlikely to find this wire size in heavy-duty kitchen appliances or power tools. However, it has an important role to play in regular life.
How Many Amps Can 20 Gauge Wire Handle?
A 20AWG conductor can carry 11 amps. However, that specifically refers to a temperature rating of 75 degrees C. But at 60 degrees C, the amp rating falls to 5 amps.
20 Gauge Wire Amp Rating
| Gauge | 60°C | 75°C | 90°C |
| 20 | 5 Amps | 11 Amps | – |
If you don’t understand the side effects the temperature can have on the wire’s carrying capacity, you may select the wrong size for your application.
An application will encourage you to use 20AWG conductors without revealing the temperature rating. They won’t tell you that a lower temperature rating denotes a low current carrying capacity.
They won’t say anything about how a setting’s ambient temperature affects the cable’s temperature rating. Therefore, a 20AWG line may overheat even though it is the recommended size for the task at hand.
This is why professional contractors are so handy. If you consult one, he will remind you that 20AWG will only carry the 11 amps you have in mind at 75 degrees. At 60 degrees, any application that exceeds five amps is a danger.
You can force a wire to transmit as many amps of electricity as you want. However, you have to remember that electricity generates heat as it traverses a conductor.
If you increase the current, the heat it generates will rise as well. At a certain point, the heat will exceed the limits of the wire, melting it.
Copper has a higher melting point than aluminum. However, that doesn’t mean you can abuse a 20AWG copper conductor by exceeding its capacity. Copper has its limits.
What does this mean for you? When you study the many tables the internet has published, don’t make the amp rating your primary focus. On its own, the amp rating is just a number.
It doesn’t tell you anything. You have to interpret the meaning of the amp rating in relation to the other tidbits of information the table will provide, such as the resistance, material, and temperature rating.
Take the tables on The Engineering Toolbox as an example. The 20AWG amp ratings it has published account for the number of cores in the cable. How many cores does your line have?
If your engineering project’s instructions have mentioned the number of cores, you have to use the information in a table like the one The Engineering Toolbox has provided to determine whether or not 20AWG is a sufficient wire size for the project.
As you can see, an electrical contractor’s job is not limited to installing wires. They have to make difficult decisions regarding wire sizes and temperature ratings.
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How To Calculate Exact Amps For 20 AWG?
You don’t have to calculate the amps. You can find everything you need in tables like the one Wikipedia has published. This Wikipedia page is very educational because it has provided a litany of equations that reveal the best way to calculate the wire size.
Most of you won’t understand the symbols included in the equations. Engineers use them to perform complex calculations, but they don’t mean anything to the layperson.
This is why the same page has gone a step further and published a table that shows you the amperage of 20AWG wire. They expect this wire size to carry 11 amps.
They have also revealed the measurements of 20AWG wire in inches, mm, kcmil, and mm2. They have even published the resistance per unit length. You can find all the information you need in this table.
It isn’t the only one. Tables like this one are easy to find online because contractors use them to make engineering decisions. Don’t ignore those details. They will affect your wire selection.
If you see ‘20AWG’ on your cable, you may wonder what ‘AWG’ means. Those letters stand for ‘American Wire Gauge.’ They signify the wire gauge. People use ‘AWG’ in some cases instead of ‘Gauge’ because the American Wire Gauge standard is a North American measurement system.
Engineers started using it in the 1850s. It has become commonplace in the US. Some contractors prefer ‘MM2.’ But AWG is still the norm in North America. The unit simplifies the process of determining and interpreting the size of a wire.
Does Distance Affect 20-Gauge Wire Amp Rating?
You cannot select the appropriate wire size for an application without taking the distance into account. By increasing the distance, you also raise the resistance. This is problematic because a high resistance reduces the amount of electricity reaching the device at the end of a conductor.
Does this mean longer 20AWG cables have a lower amp rating? Not at all. The amp rating is the current carrying capacity of a line. The numerical figure shows you the amount of electricity a conductor will carry without overheating.
That number doesn’t change. A 20AWG wire has an amp rating of 11 amps at 75 degrees C. If you increase the wire’s length by a hundred feet or more, you cannot expect the conductors to deliver 11 amps to the equipment on the other end.
The voltage drop will reduce the current drastically. However, the wire’s amp rating hasn’t changed. It can still carry 11 amps safely under ideal circumstances. But the circumstances are no longer ideal because you increased the length beyond the reasonable threshold.
Does Voltage affect 20-Gauge Wire Amps?
When contractors are trying to select the best wire size for your home’s circuit, they don’t consider the voltage. This is because the voltage affects the insulation, not the amperage. The voltage matters to engineers who oversee projects with massive voltage requirements.
The voltage is not an essential consideration for the average homestead, not for the wire size.
How Many Amps Can 20 Gauge Wire Handle At 12 Volts?
11 Amps
How Many Amps Can 20 Gauge Wire Handle At 24 Volts?
11 Amps
How Many Amps Can 20 Gauge Wire Handle At 120 Volts?
11 Amps
Does Material (Copper/Aluminum) Affect 20 AWG Amp Rating?
Copper has a greater conductivity than aluminum. You cannot replace a copper conductor with an aluminum wire of the same size. The aluminum line should be thicker than copper to match the current carrying capacity of copper. A 20WG aluminum wire is more likely to overheat if you use it in the place of a 20AWG copper line. Thus, material matters.
I want you to follow the two gauge size rule. If you’re going to use aluminum in place of copper, find the size of the copper wire and raise the gauge by two sizes for aluminum.
What Does The NEC Say About It?
The NEC associates 20AWG wires with 11 amps. 20AWG equates to 0.518 mm2, 0.812 mm, and 0.0320 inches.
Uses of 20-Gauge Wire
20AWG is a low-voltage conductor. It is quite common in LED lighting, toy batteries, and strip lights.
The wires are thin and flexible. As such, they are very easy to manipulate. Electricians use 20AWG when they want to make quick installations. You can also see this wire size in automotive applications.
The wires seem delicate, but they have a smooth surface with insulation that defends against acids and grease. They have a temperature rating that ranges between -40 and 80 degrees C.
You can also see 20AWG in jewelry, which is not surprising when you realize that the cross-section is just 0.518mm2.
20 Gauge Stranded Wire Amps
20AWG wire can carry 11 amps, regardless of whether it is solid or stranded.
The stranded wires are thinner, boasting more air gaps, resulting in a lower current carrying capacity.
Solid cables are appealing because they are resistant to extreme weather and corrosive elements. They are also inexpensive. People pair them with heavy-duty applications that require a lot of electricity.
Stranded cables have bundles of stranded wires. They are delicate, which is why they appear in speakers and circuit boards. People like them because they are malleable and flexible.
Most prefer solid wires because they are durable and inexpensive. Additionally, they are thicker, which allows them to carry more current.
20AWG-stranded cables are not the same as 20AWG solid wires.
A contractor will choose between stranded and solid wires after analyzing the unique demands of your project. But generally speaking, you can expect 20AWG stranded wire to carry 11 amps.