How to add a subpanel breaker box

Adding a subpanel breaker box is a relatively straightforward process, but it's essential to follow proper electrical safety guidelines and local building codes. Here's a step-by-step guide to help you through the process:

Before You Start

  1. Check local building codes and regulations: Verify with your local authorities that you're allowed to add a subpanel breaker box and comply with any specific requirements.
  2. Turn off the main power: Switch off the main electrical power supply to the circuit at the main breaker box or fuse box. Verify that the power is off using a voltage tester.
  3. Identify the subpanel location: Choose a location for the subpanel breaker box that's easily accessible and not prone to moisture or physical damage.

Step 1: Prepare the Subpanel

  1. Choose the right subpanel: Select a subpanel that matches the voltage and amperage rating of your main electrical service. Common subpanel sizes are 12, 24, or 48 circuits.
  2. Mount the subpanel: Install the subpanel on a sturdy, non-combustible surface, such as a wooden or metal plate. Ensure the subpanel is level and securely fastened.
  3. Connect the subpanel to the main breaker box: Run a cable (usually 10 AWG or 12 AWG) from the main breaker box to the subpanel. Connect the cable to the subpanel's main lug and the main breaker box's lug.

Step 2: Add Breakers and Connectors

  1. Install breakers: Install the correct number and type of breakers (e.g., 20A, 30A, or 50A) in the subpanel. Make sure they're compatible with the subpanel's voltage rating.
  2. Connect the breakers: Connect the breakers to the subpanel's bus bars or lugs. Ensure the connections are secure and meet local electrical codes.
  3. Add connectors: Install connectors (e.g., wire nuts or connectors) to connect the subpanel's breakers to the main circuit wires.

Step 3: Connect the Main Circuit Wires

  1. Identify the main circuit wires: Identify the main circuit wires that will be connected to the subpanel breakers. These wires should be sized according to the subpanel's amperage rating.
  2. Connect the main circuit wires: Connect the main circuit wires to the subpanel breakers using the connectors installed in Step 2.

Step 4: Test the Subpanel

  1. Turn on the main power: Switch on the main electrical power supply to the circuit.
  2. Test the subpanel: Test each breaker in the subpanel to ensure it's functioning correctly. Use a voltage tester to verify the voltage at each breaker.

Additional Tips and Considerations

Remember to always follow proper electrical safety guidelines and local building codes when working with electrical systems. If you're not comfortable with the installation process, consider hiring a licensed electrician.