Neutral-to-earth voltage, sometimes called stray voltage, is a condition that results when an electrical current flows through a neutral conductor. N-E voltage can be caused by a number of factors, both in and around the farm. The amounts of minerals and moisture in the soil, subsoil and rock strata, and the varying water table level can affect any grounding system and change N-E voltages. Sudden problems are usually due to electrical loads, conductors and connections.
Stray voltage occurs when electricity “leaks” from the hot wire directly to the neutral or ground wires before passing through the device to be powered. These leaks produce only small amounts of electricity. Direct contact between the neutral and hot wires would short the system and blow a fuse or circuit breaker.
Stray voltage can result from arcing at equipment connections, frayed insulation and other mechanical problems. In addition, multiple grounds that are not interconnected can create ground currents capable of shocking livestock. Leaks and non-connected ground systems create electric charges in the earth that aren’t normal when an electric system is operating properly. When these ground-based currents are present, animals or persons that contact well grounded equipment, such as metal stanchions or metal fence posts, will receive a shock as the electricity passes through their bodies. These N-E voltages, though rare, exist on all devices and are most common on farm feeding and milking equipment.