480 volt corner grounded delta: friend or foe

A review is given of 480 V corner-grounded delta service for oil fields. It is found that, although this type of service is less expensive than solidly grounded wye service, 480 V corner-grounded delta service may not provide a safe working environment if used for oil-field service. The problems found include: dangerous step and touch potentials can exist; nonautomatic isolation and location of phase-to-ground shorts; ground currents objectionable to residents living in the area; ground potentials have been known to cause solid-state starters to start in the off position; lightning arrestor application may be unsatisfactory; AC interference to communication equipment; higher dielectric stress on two phases; and higher magnitudes of transient overvoltages