Primary neutral-to-earth voltage levels as affected by system grounding, neutral separation, and load balancing

The authors report the results of a field investigation undertaken to examine how primary neutral-to-earth voltage levels on a rural distribution feeder are affected by the degree of primary neutral grounding, primary/secondary neutral separation, load balance, and feeder configuration. Activities resulting from stray voltage concerns on dairy farms have identified the above items as potentially affecting primary neutral-to-earth voltage levels. The results of this study have shown that the present preferred method of solidly bonding primary and secondary neutrals is consistent with the goal of minimizing primary neutral-to-earth voltage on rural feeders. The large amounts of supplemental primary neutral grounding, load balancing, and line reconstruction accomplished during this investigation could not reduce the primary neutral-to-earth voltage to zero. The long-term solutions for managing stray voltage at animal contact points must address the existence of primary neutral currents and the small amount of neutral-to-earth voltage that is created on and/or coupled to the primary neutral system.<>