Generators and Emergency Power Systems

Level 1 or Critical Life Safety Systems - NEC Article 700

These systems are legally required for critical facilities and include systems that are essential for the safety of human life. These systems are especially evident in the healthcare industry as equipment must be powered to maintain and support human life. It is mandated that power must be available within 10 seconds of an outage to these systems. Examples include fire alarms, exit and directional signage, emergency voice and alarm systems, automatic egress doors, etc.

Level 2 or Less Critical Systems - NEC Article 701

These systems are required by codes to light or power equipment whose failure could create hazards, hinder rescue, or hamper firefighting operations. Power must be available for these systems within 60 seconds of an outage. Examples include hospital communication systems, ventilation and smoke removal systems, sewage disposal, fire pumps, elevators, etc.

NEC Article 702

This includes equipment or systems that the business itself deems business-critical. Depending on the business's tolerance for downtime, they may choose to voluntarily apply stringent emergency and legally required standards. The systems that are included as optional standby differ for every facility and depend on what is most critical for business continuity and operations. The overall scope and power requirements of optional standby systems greatly affect the generator size. If the standby generator is overloaded in the case of an outage, the optional standby systems are the first to get disconnected.

NEC Article 708 - added in 2008 in response to the 9/11 terrorist attacks and the Hurricane Katrina disaster

These systems are required in facilities that, if destroyed or incapacitated, can disrupt national security, the economy, public health, or safety. Government agencies can designate any facility as a “designated critical operations area" which requires them to comply with more stringent codes. Examples include police stations, fire stations, emergency call centers, telecommunication carriers, data centers, and other critical infrastructure.