20-Amp Circuit Breakers: What You Need to Know

Each time you need to run an electrical load, you turn to your breaker box 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 they work and how to choose a compatible breaker for a rated load makes you a better electrician.

In this article, we will study a 20-amp breaker, and the uses.

What is a 20-amp Circuit Breaker?

20 amp breaker

A 20 amp circuit breaker is a type of switch gear used to protect our residential homes from surge.

It is a type of outlet used on sockets and power circuits to protect against overload and short circuits.

This breaker can withstand a maximum load of 2400 watts before tripping off.

What is it used for?

The 20 amp receptacle is connected to the power circuits and sockets wired to the 120 volt circuits.

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

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

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

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 in 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.


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 seven years of work experience in electrical installations and repairs.