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.
