How to choose breaker size

Choosing the right breaker size is crucial to ensure safe and efficient operation of your electrical system. Here's a step-by-step guide to help you select the correct breaker size:

1. Determine the load: Identify the maximum current (amperage) that the circuit will carry. This includes the sum of all connected loads, such as lights, appliances, and motors.

2. Calculate the total load: Add up the current ratings of all connected loads. For example:

3. Choose the correct breaker size: Use a breaker size chart or consult with a licensed electrician to determine the correct breaker size. A general rule of thumb is to choose a breaker size that is 125% of the total load. In this example:

Round up to the nearest standard breaker size, which is typically 30 amps, 40 amps, 50 amps, etc.

4. Consider the voltage: Breaker sizes are typically rated for specific voltages (e.g., 120V, 240V). Ensure the breaker you choose is compatible with your system's voltage.

5. Check local building codes and regulations: Familiarize yourself with local building codes and regulations regarding breaker sizes and ratings.

6. Consider the type of breaker: There are different types of breakers, such as:

7. Verify the breaker's interrupting capacity: Ensure the breaker's interrupting capacity (AIC) is sufficient to handle the maximum fault current in your system.

8. Consider the breaker's rating for continuous current: Ensure the breaker's rating for continuous current (amps) is sufficient to handle the maximum load.

Here's a simple example:

Remember to always consult with a licensed electrician if you're unsure about choosing the correct breaker size for your specific situation.