Stray voltage is the non-technical term for a phenomenon know as "neutral-to-earth voltage". Occurring most frequently in barns, it can result from poor or deteriorating wiring, faulty equipment, or improper grounding. In addition, the normal load current flowing in our system neutral and to ground creates neutral-to-earth voltages.

Neutral-to-earth problems seem to be more prevalent on farms due to increased use and complexity of electrical farm equipment. Farm animals, particularly dairy cows, are sensitive to low voltage levels. Stray voltage is a small voltage (usually less than 10 volts) that may affect animals as they contact metal objects, including pipes, stanchions, water cups and feeders. Dairy cows are ten times more sensitive to electric currents than humans.

If one or more of the following symptoms persist, neutral-to-earth voltages may be a contributing factor:

• Uneven milk out
• Cows are nervous in milking area
• Increased mastitis
• Reduced feed intake in the parlor
• Reluctance to drink water
• Lower milk production

Stray voltage has other symptoms, but these are the most common. Remember, stray voltage is only one of several factors that can cause these symptoms. Nutritional disorders, mastitis control methods, sanitation conditions, disease management methods, treatment of cows, and other environmental conditions can also bring on these symptoms.

To reduce chances of neutral to earth voltage:

• Make sure 120-volt loads on the farm are properly balanced.
• Motors used in dairy operations should operate at 240 volts allowing for a definite load balance.
• If 120 volt motors are used, they should not be started or stopped during milking operations.

For assistance with neutral to earth voltage problems:

• Initial contact should be made with a licensed electrical contractor to make certain that wiring meets the minimum requirement of the national electrical code.
• If a problem does exist, People's Cooperative Services will work with your electrician and recommend preventive measures.
• For new dairy facilities, follow proper construction methods to eliminate the chance of neutral to earth voltage problems. Contact your extension office or the Ag Engineering Department at the University of Minnesota.

For further information or assistance, call People's Cooperative Services at (507) 288-4004.