by Frank Waterer & Bill Brown, PE

In order for data centers and related facilities to properly operate as designed and intended, it is extremely important that care be given to the effective installation and maintenance of bonding and grounding systems. This paper presents the fundamentals of power system grounding, fundamental definitions and requirements of the National Electrical Code® (NEC®) with respect to grounding, the need for low voltage ground fault protection and how it is implemented, and special grounding requirements imposed by the data center operating environment. This paper also provides a summary of the applicable NEC articles, a review of clauses from specific IEEE® Standards, and listing of other references related to bonding and grounding in data center facilities. This paper also outlines and explains the principal purposes for an effectively bonded and grounded system. Also addressed are the requirement of four-wire systems versus three-wire systems, arrangements that require the installation of modified differential ground fault (MDGF) protection system, and the effects of system grounding upon surge protection and power quality. This paper reviews common installation inadequacies and construction issues, and will provide a list of common conditions that cause bonding and grounding systems within data center facilities to become inadequate or deteriorated over time. Testing and maintenance requirements of grounding systems are also discussed.