How to size breaker for fire alarm control panel

Sizing a breaker for a fire alarm control panel (FACP) requires careful consideration of several factors to ensure that the breaker can handle the electrical load of the system without overheating or tripping. Here's a step-by-step guide to help you size a breaker for your FACP:

  1. Determine the total load of the FACP: Calculate the total load of the FACP, including:
    • The power consumption of the FACP itself (usually around 10-20 watts)
    • The power consumption of all connected devices, such as:
      • Smoke detectors (typically 1-5 watts each)
      • Heat detectors (typically 1-5 watts each)
      • Manual pull stations (typically 1-5 watts each)
      • Sirens and horns (typically 10-50 watts each)
      • Other devices, such as strobe lights or LED indicators (typically 1-10 watts each)
  2. Calculate the total current draw: Add up the total power consumption of all connected devices in watts (W). Convert the total power consumption to amperes (A) by dividing the total power consumption in watts by the voltage of the system (usually 120V or 240V).
    • Total current draw (A) = Total power consumption (W) / System voltage (V)
  3. Choose a suitable breaker size: Select a breaker that can handle the total current draw calculated in step 2. Consider the following factors:
    • The breaker's ampere rating (e.g., 15A, 20A, 30A, etc.)
    • The breaker's voltage rating (e.g., 120V, 240V, etc.)
    • The breaker's interrupting rating (e.g., 10kA, 20kA, etc.)
    • The breaker's thermal rating (e.g., 10A, 20A, etc.)
  4. Consider the FACP's power supply: If the FACP has a built-in power supply, ensure that the breaker is sized to handle the power supply's output current. Check the power supply's specifications to determine its output current.
  5. Consult the FACP's documentation: Refer to the FACP's documentation, such as the user manual or technical specifications, for guidance on breaker sizing. The manufacturer may provide specific recommendations for breaker sizing based on the FACP's design and intended use.
  6. Consult with a licensed electrician: If you're unsure about sizing the breaker or have any doubts, consult with a licensed electrician who has experience with fire alarm systems. They can help you determine the correct breaker size and ensure that the system is installed and configured correctly.

Remember to always follow the National Electric Code (NEC) and local electrical codes when sizing a breaker for a fire alarm control panel.