According to the NEC, how should the non-power limited fire alarm circuit disconnect be secured?

In accordance with the National Electrical Code (NEC), the disconnection method for non-power limited fire alarm circuits must be secured in the "on" position. This requirement is established to ensure that the fire alarm system remains operational at all times, especially during emergencies. The fire alarm system is a critical life safety component, and if the disconnection mechanism is inadvertently turned off or unsecured, it could lead to a failure in alerting occupants and first responders during a fire incident.

By securing the disconnect in the “on” position, it reduces the risk of accidental deactivation, thereby ensuring the system functions properly when needed. This practice emphasizes safety and reliability, critical attributes in fire alarm systems, as they are designed to protect life and property.

The other options would not support the consistent and reliable operation of the fire alarm system and could potentially create hazardous situations if the system were to be unintentionally disabled.