Farm Stray Voltage

What is Farm Stray Voltage and What Causes It?

Stray Voltage

Electrical systems, both farm systems and utility distribution systems are grounded to the earth to ensure safety and reliability. Inevitably, some current flows through the earth at each point where the electrical system is grounded and a small voltage develops. This voltage is called neutral-to-earth voltage (NEV).

Stray voltage occurs when equipment that is not supposed to be energized picks up voltage from nearby wires or equipment. It can be found at low levels between two contact points where electricity is grounded.

Farm Stray Voltage

Electrically grounded farm equipment includes metal stabling, feeders, milk pipelines or wet concrete floors.

If an animal touches two contact points with different voltage levels, a small electric current passes through the animal. This occurrence is known as ‘stray voltage’, ‘animal contact voltage’ or ‘tingle voltage’. Some livestock animals, particularly cows, are so sensitive to electric currents and voltages that they are bothered by small levels that people would not feel.

Reported livestock symptoms for stray voltage

  • Lowered Milk Production
  • Reduced Water Intake
  • Reduced Feed Intake
  • Problematic Behaviour

There are also non-electrical causes for the above symptoms such as poor nutrition, high temperatures, infectious diseases, milking machine defects, improper handling of cows and poor environmental conditions such as dirty stalls and muddy pastures.

If stray voltage is suspected, the only way to determine the cause is to have your farm tested by a trained expert.  

Causes of Farm Stray Voltage

Algoma Power Inc. designs and operates its distribution system in compliance with all applicable codes and regulations.  Our regulator, the Ontario Energy Board (OEB), requires that we regularly inspect our distribution system.

Stray voltage can originate from two sources, a utilities’ electrical distribution system and the farm’s electric system. For safety reasons, Algoma Power's neutral system is connected to a farm’s grounding system. Some voltage will always exist between the neutral system (ground conductors) and the earth. Grounding is provided to protect people and animals from shocks, but it can also cause stray voltage. On a farm, poor or faulty wiring, unbalanced farm system loading, improper grounding, defective equipment or voltages from telephone lines or gas pipelines are all possible sources.

How are utility contributions to farm stray voltage addressed?

If a utility is found responsible for contributing to farm stray voltage, the utility must take steps to lower its contribution to acceptable levels.  The particular solution will depend on the utility’s equipment servicing the farm, the extent of the problem and other technical factors.

Common ways of addressing utility contributions to farm stray voltage include installing filtering equipment at the service to the property and installing additional grounding equipment to the utility’s neutral conductors.

For more information contact our office or click on this link; Stray Voltage Customer Response Procedure