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NEC Code Requirements
for Surge Protection Devices (SPD's)


“Where any of the disconnecting means in 620.51 has been designated as supplying an emergency system load, surge protection shall be provided”. This article was added to address emergency system loads such as elevators, escalators, moving sidewalks, chairlifts and associated equipment.


“Surge protection shall be provided for Critical Operations Data Systems.” Critical Operation Data Systems is defined by the NECT as “Information technology equipment systems that require continuous operation for reasons of public safety, emergency management, national security or business continuity.”


“Industrial machinery with safety interlock circuits shall have surge protection installed”. The concern is failure of safety interlocks on machinery, causing safety risk to operators who may not be aware of disabled safety mechanisms.


“A surge protection device shall be installed between a wind electric system and any loads served by the premises electrical system.” The surge device can be on the circuit serving the wind electric system or on the load side of the service disconnect.


“A listed surge protection device shall be installed in or on the fire pump controller.” A new NEC provision requires a listed surge protection device (SPD) to be installed in or on the fire pump controller. An SPD is necessary to provide protection for the fire pump controller. A study commissioned by the Fire Protection Research Foundation found that 12% of those surveyed had damage to fire pumps due to surges.


“A listed SPD shall be installed in or on all emergency systems switchboards and panelboards.” The NEC defines emergency power systems as systems legally required to automatically supply power to designated loads upon loss of normal power. This requirement will help ensure emergency electrical-distribution systems continue to deliver reliable power to vital life-safety loads in the event of damaging surges.


“Surge protection devices shall be provided at all facility voltage distribution levels” for Critical Operation Power Systems (COPS). COPS systems include but are not limited to power systems, HVAC, fire alarms, security, communications and signaling for designated critical operations areas. Surge protection ensures that these systems will operate in an emergency situation.

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