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707 - Stray Voltage


I.          OBJECTIVE


To establish policy to govern the assistance to be made available from the Cooperative where stray voltage may exist.




A.Electric service to member-consumers is provided through a multi-grounded network.  All parts of this network are interconnected through an electrically conductive system consisting of primary and secondary neutrals and all grounded equipment and facilities.  The grounded neutral system is connected through "ground rods" driven into the soil and through electrically grounded equipment and facilities in contact with the soil.  The Cooperative has constructed this type of system because it is dictated by code, by RUS standards, and provides the greatest level of safety and reliability.


B.Every part of the grounded neutral network, including the conductors, the connections, the earth, and the contact between the ground rods and earth, has some resistance to the flow of electric current.  Due to these resistances, whenever there is a current in the neutral system, a voltage exists between it and the earth.  These voltages are reflected to all parts of the interconnected network.  Neutral-to-earth voltage occasionally does get high enough to cause some concern, and at that time the animal contact area needs to be checked to see whether any of these neutral-to-earth voltages are entering the animal contact area.  This phenomenon and its affects have been termed as "stray voltage".


C.Stray voltage is defined as a small voltage (less than 10 volts) measured between two points that can be contacted simultaneously by an animal.  Because animals respond to the current produced by a voltage and not to that voltage directly, the source of the voltage must be able to produce current flows greater than the threshold current needed to elicit a response from an animal when an animal, or an equivalent electrical load, contacts both points.


D.Some level of stray voltage is an inherent characteristic of a properly designed and bonded electrical distribution system and is not necessarily the result of electrical faults or poor wiring.  Simply by complying with National Electric Code requirements for bonding in agricultural buildings, neutral-to-earth voltage should be expected in the animal environment.




A.The Cooperative shall periodically inform the membership that the possibility of stray voltage may exist and assist member-consumers to prevent or alleviate any problems associated with stray voltage.


B.The Cooperative shall respond in a timely manner to inquiries or complaints indicating a potential stray voltage problem.  Cooperative personnel shall determine neutral-to-earth voltage levels by conducting voltage tests and installing a recording device for a period of time.


C.If the Cooperative's investigation indicates that the stray voltage levels in any of the animal contact areasexceed the level of concern, recommendations will be made in an effort to reduce the voltage to acceptable levels without undue delay.  These recommendations may require that Cooperative personnel work in conjunction with the member-consumer's qualified electrician, milk buyer, veterinarian, consultant, etc.


1.An acceptable level of stray voltage in the animal contact area shall be based on the circumstances and the scientific research available at the time of the investigation.


2.The member-consumer shall bear the cost of any materials installed by the Cooperative on the member-consumer's system as a result of the investigation.


D.A neutral isolation device may be installed by the Cooperative to isolate the primary neutral from the secondary neutral.  The following criteria apply for the installation of a neutral isolation device.


1.     Where all remedial actions by both the Cooperative, other contributing utilities and the member-consumer fail to reduce the voltage to acceptable levels and the primary system has been determined to be a major contributing factor, the Cooperative shall bear the cost of the neutral isolation device and it's installation.


2.     Connection of the neutral isolation device shall be in accordance with the National Electric Safety Code in effect at the time of installation.


3.     The Cooperative shall own and maintain the neutral isolation device.


4.     The member-consumer shall execute a written agreement with the Cooperative regarding the installation of the neutral isolation device.


E.Each investigation shall be documented by appropriate Cooperative personnel.  Documentation shall include, but not be limited to, the type of service; problem area; measurements taken; recommendations made; remedial actions taken; results of remedial actions on voltage readings; and any follow-up taken.  Copies of the documentation, analysis and an explanation shall be provided to the member-consumer.




The General Manager is responsible for administering this policy and for recommending to the Board any changes deemed desirable.


EFFECTIVE DATE:   October 30, 2014


DATE ADOPTED:     September 20, 2001

DATE REVIEWED:   July 23, 2009

DATE REVISED:       April 18, 2013

DATE REVISED:       October 30, 2014


ATTESTED:   ________________________________________

Chris Hofer, Secretary