Change Summary

• A new requirement was added for surge protection for critical operations data systems.

Expert Analysis

A Critical Operations Data System is defined at 645.2 as “an information technology equipment system that requires continuous operation for reasons of public safety, emergency management, national security, or business continuity.” A new section was added at 645.18 demanding that surge protection be provided for critical operations data systems. Type 1 and Type 2 surge-protective devices (SPD) are typically the devices installed to a particular element of the electrical system to achieve the desired surge protection and ensure reliable electrical power.

This new surge protection requirement in Article 645 correlates with 708.20(D) for Critical Operations Power Systems. Section 708.20(D) calls for surge protection devices to be provided at all facility distribution voltage levels of a critical operations power system. This requirement often results in localized surge protection as part of the manufactured equipment. This requirement at 645.18 addresses an additional level of surge protection that is needed as close as possible to the incoming supply for the critical operations data system. For surge protection to be effective, multiple levels of surge protection typically must be provided. Type 2 and Type 3 SPDs would typically be the type of device associated with this Code article.

Surge protection at utilization equipment is only one piece of the total surge protection package that is necessary to be effective. The definition of Critical Operations Data System substantiates the need for a complete and effective surge protection system. The purpose of the NEC as stated at 90.1(A) is “the practical safeguarding of persons and property from hazards that arise from the use of electricity.” This new requirement at 645.18 for surge protection provisions for critical operation data systems supports this overall purpose. Critical operation data systems are essential in weather-related events, loss of utility power, or other catastrophic conditions.

This surge protection is not meant solely for protection against weather-related events such as lightning. This surge protection also addresses internal surges caused by localized switching within the power distribution system as well as utility switching which is a common occurrence.

Servers, storage and networking equipment can only perform as well as the power that drives it. Leviton Power Distribution Units (PDUs) provide robust, reliable power to rack and cabinet applications. Choose from a wide variety of horizontal and vertical models in switched, metered or unmetered configurations, or rack-mounted units with surge protection.