In the May/June 2005 issue of Incident Prevention the cover article, "Why Single-Point Grounding Works," generated a lot of inquires about single-point worksite grounding in underground installations. The most frequently asked question was, "How do we create an equipotential zone for underground worksites?" I received inquiries from California to Maine, North Dakota to Florida. There were so many that IP asked if I could immediately address underground protective grounding for employees in this issue.