A Brief overview of the need for Surge Protection for Emergency Systems

National Electrical Code (NFPA-70) Article 700.8 Surge Protection. A listed SPD shall be installed in or on all emergency systems switchboards and panelboards. NEC 700.2 defines emergency power systems as those systems legally required to automatically supply power to designated loads upon loss of normal power. Health care, manufacturing and other facilities where emergency power systems are incorporated require a surge protective device to protect the emergency power system. Emergency power systems typically include voice/alarm communication systems in public buildings, elevators in high-rises and back up lighting systems for emergency exits.
Other applications include means of egress illumination, exit signs fire alarms and exhaust ventilation, power operated doors, smoke control systems and critical infrastructure facilities, such as cell towers, financial institutions, and airport towers.

Example: Hospitals.

NFPA 99, Health Care Facilities Code Article Generator sets shall be tested 12 times a year with testing intervals between not less than 20 days or exceeding 40 days. Generator sets serving emergency and equipment systems shall be tested in accordance with NFPA 110, Standard for Emergency and Standby Power Systems, Chapter 8.

NFPA 110, Standard for Emergency and Standby Power Systems. Automatic transfer switches (ATS). Transfer switches are required to be operated monthly per NFPA 110(10), Sec. 8.4.6 The fact is that the switching of power sources will cause high ringing transients into the downstream power distribution system threatening sensitive electronic equipment. It is sound design practice to install a Surge Protective Device (SPD) at transfer switches to prevent such disruptions to equipment within the facility.