can i change circuit breaker from 15 to 20


Is it Possible to Change a Circuit Breaker from 15 to 20?


Circuit breakers play a crucial role in keeping our homes and businesses safe from electrical hazards. They act as the first line of defense by shutting off the power when a fault or overload occurs. However, there may be instances when you need to make changes to your electrical system to accommodate new appliances or additional power requirements. One common question that arises is whether it is possible to change a circuit breaker from 15 to 20 amps. In this article, we will delve into the details of this query and explore the factors involved in such a decision.

The Purpose of Circuit Breakers

Circuit breakers are designed to protect electrical circuits and prevent them from overloading, which could result in fires or damage to the electrical system. The amp rating of a circuit breaker determines the maximum amount of current it can safely handle. For instance, a 15-amp circuit breaker can handle up to 15 amps of current before tripping, while a 20-amp circuit breaker can handle up to 20 amps. It is important to note that the amp rating of the circuit breaker should match the ampacity of the wire it is connected to.

Assessing the Electrical Load

Before considering the change from a 15-amp to a 20-amp circuit breaker, it is crucial to assess the electrical load of the circuit in question. This involves determining the power requirements of all the devices connected to the circuit and comparing them to the ampacity of the wire. If the circuit is already at its maximum capacity with multiple high-wattage appliances, changing the circuit breaker alone may not be sufficient. The wiring and devices may need to be upgraded to handle the increased load.

Understanding Wire Ampacity

Wire ampacity refers to the maximum amount of current that a wire can safely carry without overheating. The ampacity of the wire depends on various factors such as its gauge, insulation type, and ambient temperature. It is essential to ensure that the wire connected to the circuit breaker can handle the increased load before making any changes. Upgrading the circuit breaker without considering the wire ampacity could lead to overheating, melting of insulation, or even electrical fires.

Factors to Consider

1. The existing wire gauge: The wire gauge determines the thickness of the wire, with lower gauge numbers indicating thicker wires. Different gauge sizes have different ampacities and must be matched to the circuit breaker's amp rating. If the existing wire is of sufficient gauge for a 20-amp circuit, a simple breaker replacement may be possible. However, if the wire gauge is smaller, it will need to be upgraded to cope with the higher amp load.

2. The electrical load: Assessing the electrical load is crucial, as mentioned earlier. If the current load on the circuit is already nearing the 15-amp capacity threshold, increasing the circuit breaker to 20 amps without upgrading the wiring may pose safety risks. It is essential to consider the cumulative load of all devices connected to the circuit and ensure it falls within the limitations of the wire gauge and the new circuit breaker.

3. The wire insulation type: Different wire insulation types have varying ampacity ratings. For example, wires with THHN insulation have higher ampacities compared to NM (non-metallic) sheathed cables. It is advisable to consult an electrician or refer to the National Electrical Code (NEC) to determine the ampacity rating based on the wire insulation.

4. The ambient temperature: Ambient temperature can affect the ampacity of the wire, as high temperatures reduce the wire's ability to dissipate heat. If the circuit is located in an area with high temperatures, it is important to consider this factor when determining the wire ampacity and the appropriateness of upgrading to a 20-amp circuit breaker.

5. Safety first: The utmost consideration when making any changes to an electrical system should always be safety. It is crucial to consult a qualified electrician who can evaluate the specific requirements of your circuit and ensure that any modifications meet necessary safety standards.

Consulting an Electrician

Given the complexities and potential risks associated with modifying electrical circuits, it is highly recommended to consult a licensed electrician before attempting any changes. An electrician will conduct a thorough assessment of your electrical system, taking into account the factors mentioned above. They will help determine whether it is feasible and safe to change a circuit breaker from 15 to 20 amps or if additional modifications are required.


In summary, it is possible to change a circuit breaker from 15 to 20 amps, but several important factors must be considered first. Assessing the electrical load, understanding wire ampacity, and evaluating the existing wire gauge are critical steps to take. Additionally, consulting an electrician is crucial to ensure the safety and integrity of your electrical system. Remember, electrical work can be dangerous, and it is always better to seek professional advice rather than taking any risks. By following these guidelines and prioritizing safety, you can make informed decisions regarding your circuit breaker and electrical system.


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