Stray voltage is a low voltage present on grounded metal objects. Livestock are regularly in contact with metal objects and surfaces that can carry some stray voltage, such as stanchion pipes, waterlines and heated water tanks. Although stray voltage can never be completely eliminated, proper wiring and grounding go a long way toward reducing stray voltage levels.

Common causes of stray voltage include the following:

  • Faulting electrical equipment, such as motor windings shorting to the motor frame.
  • Improperly wired sub-panels.
  • Unbalanced 120-volt loads.
  • Heating element in a water heater shorting to the tank.
  • Improper grounding of electrical boxes and equipment, including trainers and fencers.
  • Dirty or damaged electrical boxes and devices, especially in damp conditions.

Proper wiring and grounding is the best way to control stray voltage. Plus, it makes your farm's electrical system safer, more reliable and efficient. Here are some specific ways to reduce stray voltage:

  • Correctly size electric service wires for load and distance.
  • Replace problem motors and controllers.
  • Convert to a four-wire system throughout the farm.
  • Replace metal conduits and switch boxes with plastic ones to avoid corrosion and other effects of damp or wet conditions.
  • Use wire rated for wet locations (UF) in parlors and around dairy barns to protect against moisture.
  • Install an equipotential plane — a grounding grid that equals out the voltage between two surfaces that livestock may touch simultaneously.

WEC Energy Group