The term stray voltage has been used for the past 40 years to describe a special case of voltage developed on the grounded neutral system of a farm. If this voltage reaches sufficient levels, animals coming into contact with grounded devices may receive a mild electrical shock that can cause a behavioral response. At voltage levels that are just perceptible to the animal, behaviors indicative of perception such as flinches may result with little change in normal routines. At higher levels avoidance behaviors may result.

The term stray voltage is often applied incorrectly to other electrical phenomena such as electric fields, magnetic fields and most recently electric current flowing in the earth. These phenomena are generally referred to as EMF or Electric and Magnetic Fields. The physiological interactions with these phenomena are different than the mild shock associated with stray voltage. For more information on EMF and other electrical exposures, go to the EMF Page.

The following is a broad range of information resources intended to increase your understanding of stray voltage. Should you have information to contribute to this Web page, please contact the MREC at mrec@uwex.edu.

Electric Utility Service Territories

Electrical Power Rates ($/kWh) in the US: based on state average residential rate

Michigan Agricultural Electric Council

Minnesota Public Utility Commission

MREC Publications

• EPRI Stray Voltage Programs, Doug Door, EPRI-PEAC (Presentation from the 2006 MREC Rural Energy Conference)
• Idaho Power's Stray Voltage Program, Paul Ortmann, Electrical Engineer (Presentation from the 2005 MREC Rural Energy Conference)
• Stray Voltage - Regulation Versus Litigation, Paul Ortmann, Electrical Engineer (Presentation from the 2005 MREC Rural Energy Conference)
• Earth Current Research Update, Douglas Reinemann, Biological Systems Engineering, University of Wisconsin-Madison (Presentation from the 2005 MREC Rural Energy Conference)
• Equipotential Planes for Stray Voltage Reduction: Installation Guidelines
• Planning Electrical Systems for Dairy Expansion
• Stray Voltage Detection: A Self-Help Guide
• The Anatomy of a Stray Voltage / Earth Current Trial from an Engineer's Perspective [Presentation given at 2004 MREC Conference]
• Educating Veterinarians on Stray Voltage [Presentation given at 2004 MREC Conference]
• Update on Pennsylvania Stray Voltage Conference [Presentation given at 2004 MREC Conference]
• Making Measurements on the Farm [Presentation given at 2004 MREC Conference]
• Installation and Operation of Fencers, Cow Trainers and Crowd Gates
• Capacitors and Capacitive Electrical Filters

National Electric Code Internet Connection

Publications

National Resources, Agriculture, and Engineering Service (NRAES)

• Stray Voltage and Dairy Farms

State of Michigan

• Complaint of Attorney General against Consumers Energy Company
  • Motion to Compel More Complete Farm Inspect
  • Summary of Consumers Energy's Testimony

State of Pennsylvania

• Review of 2003 Conference and Proceedings: Stray Voltage and Dairy Farms

University of Wisconsin [Note: The Web site downloads slowly.]

• Water, Feed and Milk Production Response of Dairy Cattle Exposed to Transient Currents.
• Review of Literature on the Effects of the Electrical Environment on Farm Animals. [Note: In 1996, DATCP prepared a catalogue of publications on the subject of stray voltage and other electrical phenomena.  This was susequently updated by Doug Reinemann in 2003.]
• Electric Fencers [Note: This presentation was given at the 42nd Rural Energy Conference (March 2004). For more information on this conference, see Archives Page.]
• Power Line Induced Current in the Earth Determined by Magnetotelluric Techniques.

Wisconsin Department of Agriculture, Trade, Consumer Protection (DATCP)

• Stray Voltage Investigator's Training CD -- online version
• Wisconsin Electrical Dairy Equipment Survey Results -Utilities conducted 76% of stray voltage tests on farms, 86% of producers were satisfied with the stray voltage test and recommendations.

Wisconsin Public Service Commission

• Stray Voltage Documents
• Uniform Interconnect Rules for the State of Wisconsin

MREC Conference Presentations on Stray Voltage Issues

• Measuring Animal Resistance and the Components of the Cow Contact Circuit, Doug Reinemann, University of Wisconsin- Madison (2007)
• Activities of the IEEE Working Group on Voltages at Publicly and Privately Accessible Locations, Chuck DeNardo, PE-WE Energies (2007)
• Using the PMI for Stray Voltage Investigations, Ricky Evants, Power Monitors, Inc (PMI); and Pete Engstrom, WE Energies
• DC Voltage and Transient Measurement and Animal Sensitivity, Chuck Forster, Phasor Labs; and Doug Reinemann, UW-Madison (2007)
• Review of Research on DC Electrical Exposure, Doug Reinemann, UW-Madison (2007)
• Transmission Under-Build and Stray Voltage Issues, Mark Cook, PSCW; Robert Fick, Alliant Energy; and Richard Reines, PSC (2007)
• Anatomy of a Stray Voltage Trial, Rodrick Lewis, DVM, JD, Warner Norcross & Judd, LLP. (2007)
• Review of Measurement Methods for Urban Stray Voltage Investigation. Chuck DeNardo, WE Energies (2007)
• Stray Voltage Measurement Workshop, Chuck Forster, Phasor Labs (2005)
• Earth Current Research Update, Douglas Reinemann, PhD., University of Wisconsin-Madison and Milking Research and Instruction Lab (2005)
• Accomplishments of the Wisconsin Public Service Commission, Dick Reines (2003)
• Updates on Recent Legal Developments in Stray Voltage, Keith Tinsey (2003)
• Final Report on Earth Current Measurements, David Alumbaugh (2003)
• Overview of Stray Voltage Instrumentation [Part 1], Chuck Forster (2003)
• Overview of Stray Voltage Instrumentation [Part 2], Chuck Forster (2003)
• Automated Meter Reading, Allen Herrman (2003)
• A Veternarian's Perspective on Stray Voltage, John R. Roberts, Wisconsin Department of Agriculture, Trade and Consumer Protection (2003)
• Demonstration of Common Electrical Measurement Errors, Richard Reines, Public Service Commission of Wisconsin (2002)
• Stray Voltage Complaint to the MI Public Service Commission, James M. Schrandt, Agricultural Services Director (2001)

Articles:

• April 1, 2001: Interconnection Standards for Distributed Generation, by Mark McGranaghan and Bob Zavadil of Electrotek Concepts, Inc.
• 1991: Effects of Electrical Voltage / Current on Farm Animals - How to Detect and Remedy Problems. USDA Publication 696. A digital copy (16.5 MB) is available on this Web site. A hard copy can be ordered through Penn State University.