How Many Amps Can a 20 Gauge Wire Handle (The Truth!)

How Many Amps Can a 20 Gauge Wire Handle

Jeff, do you know if how many amps a 20 gauge wire can handle? This is one of the questions our readers ask a lot. Well, we´ve got you covered.

Size 20 wire is pretty small and while the diameters of these wires get pretty small (all the way up to 40AWG), size 20 is leaving the standard, common residential and commercial uses behind and traveling into a world of small-use applications on tiny devices and appliances. 

So, how many amps can a 20 gauge wire handle? The amp capacity for 20AWG wire is anywhere between 5 and 11 amps, with anything higher than 5 amps requiring a temperature rating and insulation that can handle up to 75°C. Usually, the amp ratings come in threes, however, with a wire as small as a size 20, anything higher isn’t feasible. 

You also won’t find aluminum in use for 20-gauge wire as it simply doesn’t have the capacity for the requirements of this size of wire.

So there are only two types of size 20 wire that you will find and there are only two temperature ratings for them.

It’s certainly not on the “used frequently” list on any electrician’s morning setup. In fact, you have to dig a little harder to find a chart that will show you the ampacity of a 20-gauge wire.

Fortunately, there are a few sites that have the entire chart and you can view it here.

The Two Temperature Ratings for 20 AWG Wire

Size 20 wire doesn’t require a large table to cover all of the various terminology concerning diameters, temperature ratings, aluminum, copper-clad aluminum, ampacity, and more.

There are only two temperature ratings for size 20 wire and there is no chart that covers aluminum or copper-clad aluminum. 

The two temperature rating categories that size 20 wire falls under are 60°C and 75°C, with a maximum of 11 amps allowable under the higher temperature.

However, running 11 amps through size 20 wire would be like filling an already enraged gorilla up with caffeine and cramming it inside of a plastic tube.

While the wire is capable of handling it, it’s something that you probably shouldn’t do. You’ll find the traditional insulative jacketing on 20AWG wire that you find on other, small wires, such as 18, 22, 24AWG, etc. 

The insulation determines the temperature rating of the wire as a whole. Teflon and nylon insulations are going to command higher temperatures than PVC coatings. 

If you’re read anything about the ampacity of different wire gauges, you’ll have probably come across the fact that it’s not the size of the wire that determines the ampacity but the safety standards and insulative material that is used with the wire. 

The more current that travels through a wire, the hotter it gets. As current travels through a wire, the electrons encounter resistance—caused by several natural factors that have to be calculated in—this resistance creates energy in the form of heat. 

It’s simply a matter of physics. The more current that flows through a wire, the more heat energy that is created as a result of interference with the flowing electrons. Therefore, the wire gets more and more hot. 

Read also: How Many Amps Can a 6 Gauge Wire Handle (The Truth!)

What are the Uses for 20 AWG Wire?

As small as the wire is, you might assume that the uses for it are pretty limited or, at least insofar as technology is concerned, limited to a very specific corner of the technological spectrum.

However, there are quite a few uses for size 20 wire, even though it is not listed under the “common” wires table. 

Size 20 wire is often considered to be—and is actually called in many instances—”hook up” wire.

That’s because you will find 20AWG wire in a lot of hook-up applications, such as hooking up your vehicles’ lights to a trailer that you’re pulling behind you.

Computer wiring is another, a major application of size 20 wire. Not in terms of the micro and tiny parts that make up the totality of computer hardware, but the general wiring.

That includes devices that you connect to your computer or, at least, the cable connectors. 

  • Electric meters
  • Oven peripheral wiring
  • Control Panels
  • LED Lighting, including smart LED lighting
  • Battery holder wire for 9V batteries
  • Solar Panels
  • Batteries in small toys and toy cars

The list goes on and on. No doubt you have noticed how tiny the red and black wires are that are connected to the two connectors that attach to and pair with the negative and positive terminals on a 9V battery. 

This kind of battery is often found in children’s toys, portable clocks, smoke detectors, fire alarms, remote controls for drones and RC cars, carbon monoxide detectors, portable control panels, and many more. 

When we refer to 20AWG wiring in an oven, we aren’t referring to the main power source of the oven, as that is usually comprised of a 10 or 8-gauge wire, which is like comparing the Niagra Falls with a drop of rain. 

However, there are knobs, digital displays, and buttons on an oven and the primary wiring between those interactive points and a power source is done with 20-gauge wire. 

Size 20 wire is often prevalent in solar panels as well. This type of wiring is more than capable of handling the transfer and conversion of solar energy into stored electricity.

If your solar panel has a digital display, then the odds are, there is 20AWG wiring involved. 

You’ve probably seen the little, battery-operated cars that toddlers can get into and drive around in the backyard, especially if you have kids of your own.

You may be surprised to learn that much of the wiring in these vehicles are of the 20AWG variety. 

So there are a lot of applications for 20AWG wire and that’s probably going to be the case for years to come, especially when you consider the power needs that are rampant in the toy industry, which is a giant industry with seemingly more battery-powered products than grains of sand on the earth. 

Diameter of a 20AWG Wire

This is a pretty small wire and in millimeters, it only measures 0.8128mm in diameter. If you want to look at it in terms of inches, a size 20 wire measures only 0.0360 of an inch across.

This is not a large wire by any means, as the larger number associated with the wire equals a smaller diameter. 

Size 20 wire is a solid conductor, meaning it does not have several, smaller wires interwoven tightly enough to resemble and act as a solid component.

If you want to find stranded wires, you actually have to head in the opposite direction to the much larger wires. 

It’s small enough to qualify as a frequently used wire in the automotive industry, especially when it comes to lights, including headlights, high beams, signal indicators, and brake lights.

You will also find it in speaker systems, usually of the factory-designed variety, as well. 

Since the diameter and flexibility of 20AWG wire are small and flexible enough, they tend to be a useful component in tight, enclosed spaces throughout a vehicle. 

Final Thoughts

Size 20 wire can handle anywhere between 5 and 11 amps which, of course, isn’t a whole lot when compared to other wires.

However, there are a lot of useful applications for 20AWG, especially if you enjoy your speakers, Bluetooth devices, kid’s toys, digital displays, LED strips, smoke alarms, and so much more. 

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Jeff is an automotive technician, technical writer, and Managing Editor. He has held a lifelong passion for cars, with a particular interest in cars like the Buick Reatta. Jeff has been creating written and video content about transportation, automotive, electric cars, future vehicles as well as new, used for more than 18 years. Jeff is based in Boulder, Colorado.

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