According to the National Fire Alarm Code (NFPA 72), fire alarm equipment must be ____.

The requirement for fire alarm equipment to be listed is critical as it ensures that the equipment has been tested and meets specific performance and safety standards set by recognized testing laboratories. These listings indicate that the product has complied with the standards outlined in NFPA 72 and other relevant codes, which is vital for ensuring reliability in emergency situations.

In this context, "listed" means that the fire alarm equipment has undergone rigorous testing processes and received certification that signifies its capability to perform under intended conditions. This helps ensure the safety and effectiveness of fire alarm systems in residential and commercial applications, as only equipment that meets these predefined safety criteria should be used in fire protection systems.

While options like installation by certified electricians and annual inspections are important aspects of maintaining fire alarm systems, the fundamental premise of ensuring that the equipment itself is reliable begins with the requirement for it to be listed. This underpins the overall safety and effectiveness of fire prevention strategies as set forth by the NFPA codes.