High Resistance Grounding—Avoiding Unnecessary Pitfalls

The high resistance grounding (HRG) of 480-4160-V industrial power systems increases service continuity, enhances personnel safety, and reduces equipment damage when a ground fault occurs. HRG allows maintenance personnel to quickly and safely locate a ground fault while avoiding unscheduled downtime. An abundance of literature has been published on HRG practices since the mid-1970s. Recent years have seen increased application and misapplication of transient voltage surge suppressors and uninterruptible power supplies in HRG power systems. These misapplications and their solutions are discussed. Additionally, engineering oversights in the design of HRG systems are addressed, as well as operations and maintenance issues associated with an HRG system.