Best 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 Gauge Wire & Amp Rating

Any new electrical wiring work must be done carefully whether in the house or the workplace. If you are not familiar with electrical gauges and amp ratings, this article will ease you into the learning process and soon you’ll be checking your electrician’s work like a pro. Keep reading to find out all the tips to ensure the safest and best 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 gauge wire & amp rating.

How do you choose the right size?

There are not only thousands of types but also different thicknesses and materials out there for the layman to buy and install in their home. To install the correct size, you must keep in mind mainly two things – thickness and length. The thickness is measured while the amount of current the wire should ideally carry is measured through amps or amperage ratings. Both of these factors are directly related to each other. The thicker it is, the more current it can carry.

Moreover, keep in mind that an increased length can cause the current carrying capacity to drop. To tackle this, you can increase the thickness or the gauge of the so that any loss through the heat is simultaneously made up for.

What is Gauge and what are its types?

The gauge of a wire refers to its diameter and hence its current carrying capacity.

Different parts of the world use different standards for measurement. Here are the most popular types:

  • IEC 60228: This is the standard set by the International Electrotechnical Commission on international conductors of cables. It is the wire-size measurement standard used in most parts of the world.

  • AWG – American Wire Gauge is another standardization system in use since 1857 in North America. Today, this system is widely adopted in the United States and Canada. Here, like many other non-metric systems, the increasing number of AWG automatically denotes a decreasing diameter. This is similar to the British Standard Wire Gauge system. Apart from electrical wires, it is also used to denote the sizes of body piercing jewelry.

  • SWG – Standard Wire Gauge refers to the unit used to measure the thickness given by British Standards in 1964. Although originally widely adopted, it is in use in very small areas now. Today, it is only known to be used in the measurement of guitar strings and some cables.

What are different sizes used for?

circuit breaker

Let’s take a look at the most common options used in the industry and what they are used for.

2 gauge

A 2 AWG copper wire is commonly used for Central electrical heating systems. Its diameter is approximately 0.2576” and hence this size is ideal for installation in circuits where high flame retardation is required.

The rated amperage that a 2 gauge copper insulated wire can carry is 95A at 60degree. While at 75 degrees, it can carry 115A. In the aluminum form, this cable is rated 75 A at 60 degrees and 90 A at 75 degrees respectively. The celsius refers to the temperature rating of the conductors.

4 Gauge

At a 60 degrees Celcius rating, a copper conductor of this size is rated at 70 A. While it is rated 85 A and 95 A for 75 degrees and 90 degrees respectively. The 4 AWG size is generally sized at 0.2043 inches in diameter. Much like the 2 AWG type above, it is generally used in large heating systems and electric furnaces where fire safety is a major concern.

6 Gauge

The 6 AWG size is approximately 0.1620 inches in diameter. It is rated for 55A at a temperature rating of 60 degrees. While at 75 degrees and 90 degrees, it is rated at 65 A and 75 A. While in aluminum-types, the amp rating is 40 A and 50 A for 60 and 75 degrees Celcius respectively. It is generally used in electrical cooking ranges and cooktops. It can also be used in heat pumps and wiring of on-demand electrical water heaters.

8 Gauge

The 8 AWG is sized at 0.129 inches in diameter. In the copper conductor form, it is rated for 40 A at 60 degrees Celcius and 50 A at 75 degrees Celcius. While at 90 degrees celsius, the ampacity is approximately 55 A. In the aluminum form, however, the ampacity is 30 A at 60 degrees and 40A at 75 degrees.

This type is also known as hook-up wire, hot tub wire, and conduit wire, construction cable, and lighting wire. Usually covered in a nylon sheath, also known as Thermoplastic high heat resistant nylon (THHN), this size is generally used for indoor projects. The nylon jacket not only protects against damage and shock but also prevents the metal conductor from receiving any abrasion. A common use is carrying current to and from indoor light switches and appliances in homes and offices, which is why this product also goes by the name of “building wire”.

10 Gauge

10 AWG is sized at approximately 0.102 inches in diameter. In copper form, the ampacity at 60 degrees celsius is 30 A and 35 A at 75 degrees celsius. While at 90 degrees Celsius, the ampacity is 40 A. In aluminum form, the ampacity remains a fixed 25 A at both 60 degrees and 75 degrees Celcius respectively.

Some common uses of a 10 AWG wire are in the electrical clothes dryer and electric water heaters that are rated for 30A. It can also be found in 240V window air conditioners.

This wire in bare copper non-insulated form can also be used for grounding and bonding purposes. In this process, it is connected to a grounding rod and redirects any extra current to the ground in case of fluctuations.

12 Gauge

A 12 AWG is sized at 0.0808 inches in diameter and is rated at an ampacity of 20A, 25A, and 30A at 60 degrees, 75 degrees, and 90 degrees Celsius respectively. While in aluminum 12AWG, only an ampacity of 15A is supported at any given temperature rating. This type can be found in the kitchen, outdoor receptacles, and bathroom project. Apart from this, it can also be used in an air conditioner of 120V.

For outlets and lights, it’s the best option on a 15A or 20A circuit, even though it might cost you more than a 14AWG size. It is also commonly found in refrigerators in 12-2 Romex form.

14 Gauge

A 14 AWG wire is 0.0641 inches in diameter and is commonly found as part of lighting circuits due to its high flexibility and very thin size. For a visual, it has roughly the same thickness as a dime.

It is rated for 20A and 25A at 60 degrees Celcius and 75 degrees celsius. Most electricians prefer a combination of 12AWG and 14AWG in light fixtures and lighting circuits. Moreover, there has been a recent shift in demand from 14AWG to a 12AWG wire in residential projects. This can be due to the limit of 8.4 receptacles on a 14AwG circuit and a capacity of 10 receptacles on a 12 AWG circuit. Also, a 12AWG has less resistance than a 14AWG one which means less energy is wasted and an eco-friendly circuit is created.

Incorrect wire size and amp rating causing burning wire

16 Gauge

This unique size is rated for 18A at 90 degrees Celsius and is 0.0508 inches in diameter. It can be found in extension cords of light duty. Commonly found in lamp cords, it can be supply current from portable devices to current sources through wall sockets and other areas. It is also used in repair work for clocks, floor and table lamps, radios, and low-energy appliances. In stranded and TFFN-sheathed form it can also become part of fixture wiring. Automotive purposes like trucks, RV’s, and marine also feature 16AWG stranded wiring that is oil and flame resistant. Hence, overall, a 16 AWG wire is very versatile.

18 Gauge

A standard 18AWG wire comes in 0.0403 inches in diameter and is rated at 10A, 14A, and 16A at 60, 75, and 90 degrees Celsius respectively. It is generally part of lamp cords of 10 amps and low-voltage lighting. Just like 16AWG, it can also be used in automotive functions. It can also be bought for portable wiring when it has a rubber jacket covering installed on the outside to make it weather and oil-resistant. This rubber is known as a thermoplastic elastomer or TPE jacket. 18 AWG can also be used for HVAC equipment, tools, control panels, and other circuits due to its high flexibility.

20 Gauge

20 AWG is measured at 0.0320 inches in diameter and is rated at 5A and 11A at 60 degrees and 75 degrees Celcius respectively. This type of hook-up wire is mostly found within control panels, computers, meters, and ovens in both solid and stranded form. It is generally also found as flex control cables in innovations like a robotic arm or other automated machinery where a lot of moving components are present. This is because the flexibility of a 20AWG cable allows for rapid movement and flowing current to operate simultaneously without any obstruction.

In bare copper braid form, the 20AWG wire can also be used as a coaxial cable in video applications and digital devices that need audio synchronization. For example in cable TV, speaker and LAN connections.

22 gauge

A 22 AWG wire is sized at 0.0253 inches in diameter and is rated for 3A and 7A at 60 degrees and 75 degrees Celsius temperature rating respectively. This type is so thin and fragile, it is usually part of the prototyping and breadboarding projects on analog devices. In stranded form, 22AWG cable is used as communication cable connectors for fire alarm systems, networks, computer cables, and other security-related cables.

24 Gauge

A 24AWG wire is sized at 0.0201 inches in diameter. It features an ampacity of 2.1A and 3.5A at 60 degrees and 75 degrees Celsius respectively. LAN cables make use of this for transporting data that includes both audio and visual transmissions. It is also highly sensitive to temperature and hence can also be used for thermocouple wires that sense the temperature of an object and feed it to other monitoring devices.

How to install a breaker?

A circuit breaker is an essential requirement in every home’s main control panel for adequate electrical fire safety. Each time an overload or fluctuation causes a current to overflow in a circuit, the circuit breaker trips and breaks off all contact points and shuts down the circuit to prevent wires from shorting and causing a fire or blast. This makes it an essential part of every circuit and its maintenance, servicing, and a replacement must be taken seriously.

electrician installing 30, 40, 50, 60, 100, 200 amp wire

Before you begin

Before you start your project of replacing a circuit breaker, you need to know the right type, and brand of the breaker you’ll be installing.

A label near the reset button of the circuit breaker’s lever will indicate the exact requirement of the breaker you need. When you have bought this, you will also need adequate lighting or a flashlight, safety goggles, and some screwdrivers of different sizes to get going.

The Process

Here’s the full detailed guideline for replacing a breaker. Follow professional guidance if you require any additional help or have any queries regarding the installation.

  1. Shut down the main power – This is a must whenever any electrical work is being done. Even if you feel all appliances and lights are off, residual current can cause shocks and accidents. Turning off the main power in the main circuit breaker lever assures no residual current is leftover in the circuit. Carry a flashlight and plenty of batteries to continue the rest of your work.
  2. Take away the cover plate – The breaker panel has a cover that must be removed using the screwdrivers. The corner screws should be removed first and the middle ones last. Be careful never to tip the plate inside the panel while you are removing it.
  3. Deinstall the faulty breaker – Flip the breaker’s level to OFF. You will find a thick insulated black wire connected to the breaker wrapped closely to it. This must be extracted out from the panel while being careful not to touch anything else. Grasp the old faulty breaker and pull it out from the edge using a pivot motion towards the outside of the panel. With a snap sound, the breaker will break free of the panel.
  4. Remove the wires – Now pay attention to the black wire attached to the circuit and unscrew the terminal holding the wire. In a GFCI and AFCI circuit breaker, you will also have to loosen the neutral connection and a white wire running from the neutral bus bar.
  5. Reconnect it to the new breaker – Firstly, make sure to set the lever to ‘off’ on the new breaker. Take the black circuit wire and attach it to the new circuit breaker by putting the bare end under the screw terminal on the breaker. You can identify this terminal through the label of ‘neutral’ or ‘load neutral’ on the breaker. The white one must be attached to the neutral bus bar panel as well.
  6. Insert the new breaker into position – Now insert the new breaker into the empty location. You should hear the snap as it sits tight into position on the bus bar. Now wrap the excess neatly around the breaker as you found them.
  7. Put the panel cover back on – Use screwdrivers to screw the middle and corner screws of the plate into position.
  8. Turn on the power – Turn off all individual breakers before turning on the main breaker. After turning the main breaker on, flip the switch on individual breakers to ‘on’ one by one so that the power demand doesn’t shoot up instantaneously.

Lastly, it’s a good idea to test all your appliances and lighting fixtures to make sure the new breaker is operating properly.

Electrical Safety Tips

Here are a few tips to always remember around the house and office when dealing with electrical appliances and wiring.

  1. Always make sure the main power is completely off before beginning any work on the circuit.
  2. Only ever buy and use equipment with handles made of non-conducting material when you are working on electrical panels.
  3. Never wear metallic watches, pens, rings, and jewelry when working on an electrical panel or appliances.
  4. Wear insulated materials like rubber gloves, shoes, safety goggles and cotton tight clothes when working with electricity, especially if engaging in welding work. Also, make sure your hands are dry and no sign of moisture is near when you begin rewiring.
  5. If possible, work with only one hand throughout the electrical process. This can be done if one hand is kept in your pocket or holding important equipment like a flashlight on the side. This is because working with one hand reduces the chances of any electrical shock running through your entire body and especially the chest cavity, thereby reducing the chances of major electrocution accidents.
  6. Any equipment causing even the slightest sensation of electrical shock on touch should be reported for repair immediately.
  7. If any water or liquid spills onto live working equipment, do not try to wipe it off. Instead, first, disconnect the equipment from the power source and wait for the residual current to pass off.
  8. Never store highly flammable liquids and products near electrical equipment. For instance, gasoline, kerosene, oil bottles, deodorant bottles, and even sanitizers should be kept well away from electrical appliances, especially those with higher chances of flame ignition like a heater.
  9. Never wear loose clothing while working with electricity.
  10. If any circuit panel work or appliance repair is to be left open and unattended, make sure it is powered off and a sign is placed indicating ‘repair’ work and ‘caution’.
  11. Keep appliances and devices away from wet areas like a bathroom and kitchen. If you must use them, use them only with a GFCI outlet.
  12. Always keep track of the number of devices and lighting fixtures on a circuit and never overload it.
  13. Use diagonal cutters instead of pocket knives to ensure a cleaner cut on the cable.
  14. When using an extension cord, make sure the amperage rating matches your attached devices.
  15. Never run cables from under carpets and other cloth to prevent chances of fire.
  16. Never tug on a cable of the device to unplug from the socket. Always grab the plug and pull to keep chances of fraying and damaged cords which can later prove to be a hazard.
  17. Only use the recommended wattage in light fixtures and lamps.
  18. Never turn on the individual breakers all at once after repair work is finished. Turn them on by one to avoid sudden power demand from the main breaker which can lead to overloads and blasts.
  19. Whenever any extension cord, plug, or device feels warm or hot to touch, stop using the device and get it checked by an electrician before using it next.
  20. Always call a professional whenever unsure about electrical equipment or panels. A licensed electrician must be on call until you turn expert on electrical work.

We’re sure our knowledgeable article about the correct ampacity of each gauge must have helped you on the way to becoming a responsible homeowner. Make sure to follow our handy safety tips and detailed instruction guide on how to install a breaker and show off your skills to your guests and friends!

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