What voltage is required for primary power sources for smoke detectors in newly constructed homes?

The required voltage for primary power sources for smoke detectors in newly constructed homes is 120-volt AC. This standard is established by the National Fire Protection Association (NFPA) and the International Residential Code (IRC), which both emphasize that smoke detectors should be connected to a reliable power source to ensure their constant operation.

Using 120-volt AC is advantageous because it allows for the interconnection of multiple detectors, meaning that when one detector is triggered, all interconnected units will sound an alarm. This feature significantly enhances safety by ensuring that occupants are alerted regardless of where they are located in the home.

While options such as 24-volt AC or 12-volt DC might be used in certain applications, these voltages do not meet the typical requirements for residential smoke detection systems, which prioritize reliability and effective interconnectivity for safety. Additionally, 220-volt AC is not suitable for smoke detectors in residential settings as it is primarily used for larger appliances. Hence, the choice of 120-volt AC aligns with established safety codes and practices for ensuring effective smoke detection in homes.