20 Amp Circuit Breaker: Everything You Need to Know.

Each time you need to run an electrical load, you turn to your 20 amp breaker for help. These protective devices have been around since the invention of electricity.

But while they might look like a no-brain device, understanding how the device works and how to choose a compatible breaker for a rated load makes you a certified electrician.

In this article, we will study a 20-amp breaker, types, uses and installation guide.

What is a 20 amp Circuit Breaker?

A 20 amp circuit breaker is a safety device used to stop the flow of faulty currents on a 20 amp circuit. It helps protect residential homes and appliances from electrical surges and short circuits.

Types of 20 amp circuit breakers

20 A breakers fall into two categories, they include:

  • Single pole 20 amp circuit breaker
  • 2 pole 20 amp breaker.

Single pole 20-amp breaker

A single pole 20 amp breaker handles a maximum voltage of 120 volts, and a current of 20 amperes. It comes with a neutral and one hot wire.

Single pole breakers are ideal for low powered appliances such as light fixtures and fans.

2 poles 20 amp breaker

This double pole breaker comes with 2 hot wires, a neutral and can handle a maximum of 240 volts.

It is used to protect heavy machines such as dryers, electrical stoves, water heaters and air conditioners..

What is a 20 amp circuit breaker used for?

A 20 amp breaker is connected to the power circuits and sockets wired to a 120  or 240 volt circuits.

It is used for plugging appliances, laundry, and bathroom circuits.

It is also used in the kitchen for plugging fridges, but not for high voltage consumers like cooker units that require 30 amp circuit breakers.

What size wire do I need for a 20 amp circuit?

A 20-amp circuit breaker requires a 12 gauge wire for optimum performance and maximum protection. Using the wrong gauge of wire can lead to overload or fire hazard.

See this table for more details

Circuit breakers Wire size/Gauge

Circuit Breakers (Amps)Wire Size/GaugeWhere it is used
200 Amps3/0 GaugeService entrance
150 1/0Feeder wire and service entrance
1003Feeder wire and service entrance
50/556Large appliances and feeder wire
408Large appliances and feeder wire
3010Air conditioning, dryers, and appliances
2012Appliances, bathroom circuits and laundry
1514Light bulbs and small appliances

How many outlets can a 20 ampere circuit carry?

Normally, a single outlet draws a maximum power of 180 watts (1.5 amp), while a 20-amp circuit carries a maximum load of 2400 watts before tripping.

If you multiply 1.5 amp by 13, you get 19.5 amp. This means you can plug in 13 devices at a time.

But can this give the desired result?

The answer is no. Plugging up to 13 devices into one circuit may not allow even distribution of power within the device, and some may not get enough power to start up.

Also, loading the circuit up to 90% will cause the breaker to trip. That is why the National Electric Code (NEC) recommends 80% or less for breakers and circuits.

This 80% rule is important because a sudden surge from big appliances may consume the remaining 20% which serves as a free space in the circuit.

Therefore, a 20-amp circuit can comfortably carry a load of 1920 watts or 16 amps on a 120V system without going off.

If you divide 16 amp with 1.5 amp, you get 10.67.

So the number of outlets a 20 amp circuit can carry is 10.

Difference between a 15 and 20 amp breaker

The two products are the same and also do the same work. Their difference only lies on the amp and the gauge of wire they use.

15 amp uses 14 gauge wires, while 20 amp uses 12 gauge wires.

The 20 amp also protects higher appliances like fridges and laundry. While 15 amp protects light bulbs and smaller equipment.

Can I replace a 15A circuit breaker with 20 amp?

Yes, you can upgrade your 15 amp to a 20-amp circuit if you have heavy appliances.

But before changing the breaker, make sure your wiring has a normal gauge wire, which is a 12 gauge, that can carry that level of current safely.

Once the wire gauge is normal, replacing the breaker will only take a few minutes.

However, if the branch circuit is a 14 gauge wire, replace it with a new 12-gauge before installing the outlet.

For compatibility reasons, you should not install a Square D homeline breaker from Schneider Electric into the Eaton breaker panel.

How to install a 20-amp circuit breaker

Installing a 20 amp breaker requires working with electrical components. If you are not experienced in breaker box wiring, it is necessary that you hire a licensed electrician. 

If you have the skills, this guide will help you wire a 20 amp breaker correctly.

Required tools and materials

  • Screwdrivers
  • Wire striper
  • Wire cutter
  • 12 gauge wire
  • 20 amp rated breaker
  • Voltage tester.
  • Rubber gloves

Installation procedures

Turn off the power source

Locate the main breaker that controls the power and turn it off. This is to ensure maximum safety during the installation process.

Remove the panel cover

Using your screwdriver, loosen the screws holding the cover and remove it from the main breaker box. Open one knockout cover with your plier and pass your wire through the hole.

Connect the ground, neutral and hot wires.

You can identify the wires by their color. The neutral wire is usually white, the ground is green or a bare copper wire while the hot is black or red.

Strip the wires and connect the neutral wire to the neutral bus bar, the ground to the ground bar, and the hot wire to the circuit breaker.

Plug the breaker into the panel board and press it to snap in.

Put back the panel cover

Before you cover the panel, make sure the wires are in order and none are hooked by the panel cover. Once it is ok, cover the panel and turn on the main switch.

Note: If you want to turn on the power supply of your breaker, start with the main switch and then the branch circuit breakers.

This is to prevent power surges that may arise when electricity is suddenly turned on. 


The regulations in the NEC are put in place to ensure we apply safe practices when using electricity in the home.

You should not change the electrical system in your home that contravenes any of these regulations since they are there to make the systems safer in the house.

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About mariaelectricals

Hi, I am Emmanuel Nwankwo, a commercial electrician and the founder of mariaelectricals.com. I established this blog to share my decades of work experience in electrical installations and repairs.