A SELF-HELP GUIDE Stray Voltage Detection Table of Contents 2

Introduction ...... 3

What is Stray Voltage ...... 4

Types of Voltage Encountered ...... 4

Causes of Stray Voltage ...... 4

Detection of Stray Voltage...... 5

Making Electrical Measurements ...... 6

Recording Voltage Data ...... 7

Interpreting Voltage Data ...... 7

Monitoring Stray Voltage ...... 8

Farmers’ Stay Voltage Checklist ...... 9

Stray Voltage Data Sheet ...... 10

Mission Statement ...... 11 Introduction 3

or a number of years, stray voltage has been a concern among livestock farmers, particularly those with dairy Fherds. This booklet has been prepared to give you a basic under- standing of stray voltage, some of its common causes, how to determine if it exists on your farm at levels that may be harmful, and when to call for assistance to minimize it. “A Self-Help Guide To Stray Voltage Detection” is not in- tended to make anyone a stray voltage expert, but should provide you with the information necessary to safely determine whether or not a significant level of stray voltage is present on your farm at locations that are accessible to your livestock. This booklet is specifically oriented toward the dairy farmer; however, most of the information provided is applicable to all livestock operations. The Farmers’ Stray Voltage Checklist, located on page 9, is included to assist you in visually inspecting your farm’s electrical system and noting potential stray voltage sources. A Stray Volt- age Data Sheet, located on page 10, is included to help you record milkhouse and barn area voltage measurements. In addition, this booklet tells you how to use or install your own voltmeter to monitor stray voltage levels—a practice that is strongly recommended for all livestock operations. What is Stray Voltage? 4

WHAT IS STRAY VOLTAGE? duction, mastitis, or behavioral Symptoms present, but no tingle ow levels of AC (Alternating problem. shock sensation Current) voltage on the Livestock may feel voltages not Lgrounded conductors of a TYPES OF VOLTAGE sensed by humans because an farm wiring system are a normal and ENCOUNTERED animal’s body resistance is less than unavoidable consequence of operat- t is important to make a distinc- that of a human. ing electrical farm equipment. These tion between low-level stray Voltage measurements should be voltages are termed “stray voltage” voltage and the more hazardous taken whenever livestock exhibit I symptoms which reportedly have when they can be measured between voltages which produce a painful two objects which may be simulta- shock. been attributed to stray voltage. neously contacted by animals. You may take your own voltage Occasionally, stray voltage is signifi- Personal shock measurements to determine the cant enough to be felt by you as a If you experience a painful presence, or level, of stray voltage “tingling” sensation, particularly if personal shock when you touch a and whether corrective action might you have a cut at the point of metal object in the barn, you are not be required. If you are unsure how contact. feeling stray voltage. Personal to take these measurements, you can This booklet concentrates shocks usually indicate defective ask for assistance from your local exclusively on measuring and mini- wiring or equipment. Since these utility office. mizing AC voltages. Small levels of conditions are hazardous and could DC () voltage also may start a fire, call an or your CAUSES OF STRAY be present on farms but are gener- local utility immediately. VOLTAG E ally not a concern. tray voltage on a farm is Tingle shock typically the result of several REPORTED SYMPTOMS If you feel low-voltage “tingling” Svoltage sources acting simulta- ymptoms reportedly attributed when you’re in the barn, it is pos- neously. Both on-farm and off-farm to significant levels of stray sible that your livestock may be sources may contribute to the level Svoltage include uneven experiencing a similar sensation. of stray voltage present. A common milkout, decreased milk production, Tingle shocks felt when touching on-farm source of stray voltage is the and increased incidence of mastitis. electrical devices may indicate an result of the interconnection of Cows may be reluctant to enter the internal short in the equipment. If equipment grounding conductors barn or milking parlor, may be this happens, you should call your with the neutral conductors of the nervous and “dance” in their stall. electrician. Tingle shock from non- farm wiring system. The grounding They also may be reluctant to eat or electrical metal objects frequently conductor is used to metal drink, and feed consumption may be can be eliminated through better equipment and should never be one inconsistent for no apparent reason. bonding (electrically interconnecting of the conductors used to supply It is important to note, however, metal objects) and grounding. It is power. The neutral, or other conduc- that these same symptoms can be recommended that you continue to tor supplying power, should never be the result of numerous other non- take voltage measurements after connected to the metal case of electrical farm factors. As a farm improving bonding and grounding. equipment or be interconnected with manager, you should investigate all Continuing measurements will the grounding conductor at any possibilities, including stray voltage, assure that these changes have point other than the main electric when attempting to resolve a pro- reduced the voltage that animals service panel for the building. may experience to an acceptable Other on-farm sources of stray level. voltage are electrical shorts in Detection of Stray Voltage 5

equipment, defective underground DETECTION OF STRAY than stray voltage (cow-contact cable, unbalanced 120-volt loads VOLTAGE USI NG measurements). including loads in the house that VOLTM ETE RS CAUTION: The resistor MUST cause voltage drop on neutral ou can detect the presence of be removed from the meter before conductors, corroded bonding stray voltage on your farm using the meter to measure ener- connections, corroded neutral safely and easily by using a conductor connections, and missing Y gized conductors. voltmeter to measure the voltage or inadequate grounding systems. between two points that may be The normal operation of electri- simultaneously contacted by live- You may use either a digital cal equipment (such as welders, stock. voltmeter or an analog (needle-type) motors, pumps and conveyors) in voltmeter to measure stray voltage. remote areas of the barn or other CAUTION: For your own safety, do However, you must understand the buildings may also result in stray not attempt to make electrical limitations of each in order to ensure voltage within animal confinement measurements on accurate and meaningful measure- areas. The degree to which these or within electrical boxes or cabi- ments. sources contribute to stray voltage nets unless qualified to do so. levels depends upon many factors Digital voltmeter including the layout of the farm SUITABLE VOLTMETER A digital voltmeter with a 500- wiring system. ohm shunt resistor is easy to read any of the voltmeters in use A visual inspection checklist of and ideal for monitoring stray voltage today can give you mislead- potential on-farm problems (Farm- levels. ing readings because of the ers’ Stray Voltage Checklist) is M A digital voltmeter without a manner in which they are con- included in this booklet on page 9. shunt resistor has an extremely high structed. A suitable voltmeter must Correction of on-farm deficien- input resistance (several million ohms not be affected by DC voltage when cies will normally require the ser- compared to 10,000 to 25,000 ohms operating on the AC scale. The vices of a qualified electrician. for an analog voltmeter). This high- meter should also “screen out” weak Off-farm voltage sources may input resistance makes it very sensi- voltage sources which are incapable also be present on your farm. If tive to weak voltage sources. Weak of affecting your livestock. A shunt requested, your local utility will voltage sources, however, do not have resistor is used for this purpose. conduct an investigation utilizing the ability to affect your animals. In order to accurately measure controlled, standardized test proce- In order to accurately measure the stray voltage that livestock may dures to determine to what extent voltages which your livestock may feel, a shunt resistor, approximately electrical distribution facilities or feel, you must make your voltmeter equal to the resistance of a cow other off-farm sources contribute to “look” like a cow (electrically) by (about 500 ohms), should be con- stray voltage levels. If an abnormal connecting a 500-ohm shunt resistor nected across the voltmeter leads. contribution is found, your local across the voltmeter leads. (See (Refer to Figures 1 and 2 on utility will take action to help reduce Figure 1.) (This type of resistor is page 7.) A two-watt, flameproof the level of stray voltage on your available at most electronics parts resistor of approximately 500-ohms is farm. Even if the off-farm contribu- stores.) recommended as a meter shunt for tion is found to be normal, they may measuring stray voltage. make minor system modifications to Analog Voltmeter NOTE: The shunt resistor should help reduce stray voltage levels. The digital voltmeter is the be removed from the meter before preferred method of monitoring stray making any measurements other voltage. However, if you use an analog Making Electrical Measurements 6

voltmeter, it must have a voltage point-to-point method and the point- investigator diagnose the sources of scale sensitive enough to accurately to-reference ground method. stray voltage and involves the use of display voltages less than 1.0 volt AC. a remote ground probe as a refer- Point-to-point measurement method A meter with a full-scale reading of ence. The point-to-point method allows 2.5 volts AC is ideal. A full-scale For reliable accuracy, the remote you to determine the levels of reading of 5.0 volts AC is normally ground probe should consist of a voltage which may potentially affect acceptable. Any full-scale reading metal stake or rod driven into moist the animals. This is the most impor- greater than 5.0 volts AC is generally soil and located at least 30 feet away tant measurement and it simply not sensitive enough for stray from any electrical grounds, water means taking voltage measurements voltage measurements. pipes or grounded metal equipment. between two points which may Your analog voltmeter also must An insulated wire (no. 18 is ad- simultaneously be touched by be capable of measuring only AC equate) should then be used to livestock. Usually this will be from voltage. Some analog voltmeters will connect the ground probe to the metal equipment, such as drinking not discriminate between DC and AC common terminal of the voltmeter. cups, water pipes and stanchions, to voltage and may provide you with The other voltmeter probe is used to the floor. misleading information. contact the metal objects within the The meter lead in contact with An analog voltmeter can be animal confinement area. The 500- the floor must be in a wet location tested by setting the meter on the ohm shunt resistor is not used. with good contact pressure to AC scale and touching the leads to This method of measuring ensure electrical contact. Attaching the ends of a 1.5 volt battery. The usually results in higher voltage the lead to a copper plate placed on leads should then be reversed and readings than the point-to-point the wet concrete floor is the recom- the procedure repeated. If the method. However, it is not a mea- mended method. However, from a meter’s indicating needle initially surement of animal exposure because practical standpoint, other alterna- “jumps” and then settles to a steady an animal cannot simultaneously tives such as standing on the voltme- reading of 0.0 volts, the meter is contact these two points and, there- ter probe or clamp, or attaching the acceptable. fore, cannot be harmed by the clamp to a wet barn cleaner may The use of an analog voltmeter measured voltage. work satisfactorily in many cases. with a 500-ohm shunt resistor will When you take the measure- Practical suggestions result in an accurate measurement ments, twist or scrape the clamp Most voltmeter leads are too of the stray voltage which may be when attaching it to make sure that short to make point-to-point voltage perceived by your livestock. there is good electrical contact. measurements. You may want to use The point-to-point measurement a set of light-duty car battery jumper MAKING ELECTRICAL method, which uses a copper plate cables to extend the length of the MEASUREMENTS on the floor in the rear-hoof area voltmeter leads when making mea- and a 500-ohm shunt resistor across surements to the various metal CAUTION: For your own safety, do the leads of a digital voltmeter, most contact points. They also may be not open or attempt to measure accurately represents the actual used as temporary bonding jumpers voltage inside electrical devices or voltage which may come in contact to determine the effect of additional equipment or on any other electri- with livestock. bonding. cal wiring unless qualified to do so. When you measure voltages on Point-to-reference ground outside equipment, such as feeders measurement method here are two basic measure- or stock waterers, you may use a The point-to-reference ground ment methods for diagnosing metal rod driven 12 to 18 inches into Tstray voltage situations: the method of testing is used to help the Recording Voltage Data 7

the ground approximately six feet WHAT SHOULD YOU DO tance in conducting a stray voltage from the equipment being measured. If point-to-point voltage measure- investigation. You should have the This is an adequate method of ments, taken during milking or at voltage measurements from the determining if a voltage is present on any other time of day, do not exceed Stray Voltage Data Sheet (page 10) the device being checked. A more 1.0 volt AC, research indicates that available. thorough investigation may be the voltage is too small to affect Arrangements may be made for required to accurately measure your livestock. Under these circum- knowledgeable personnel to conduct animal-contact voltage levels. stances, it is recommended that you a detailed investigation to determine use a voltmeter in your barn to the sources of stray voltage on your RECORDING VOLTAGE DATA regularly monitor the level of stray farm. ormally, stray voltage should voltage present. Finding the sources of stray be measured during milking, voltage can be difficult and time Nwhen the highest electrical POINT-TO-POINT VOLTAGE consuming. It requires knowing loads are present and highest voltage GREATER THAN 1.0 where and what to measure, know- levels will occur. It is recommended VOLTAC ing what type of sources to look for, being familiar with the nature of that you take voltage measurements f point-to-point voltages exceed electricity, and having the ability to at several animal contact locations to 1.0 volt AC, call your local perform controlled tests using determine where the voltage is utility office to request assis- greatest. I suitable measuring instruments. Use the data sheet on page 10 for recording voltage measurements. The date and time that measure- ments were taken should be in- cluded. This information may serve as a future reference to detect any changes in your farm electrical system.

INTERPRETING VOLTAGE DATA Research regarding the levels of Wire Double Nuts stray voltage that should cause Banana concern is continuing at several Plug Banana universities. At the present time, the Plugs majority of the animal experts involved maintain that corrective 500-Ohm Resistor 500-Ohm Resistor action is not necessary for values below 1.0 volt AC. Some electric FIGURE 1: FIGURE 2: utilities have taken a conservative Digital Voltmeter with 500-ohm, Analog Voltmeter with 500-ohm, approach and recommend a stray two-watt, Flameproof Resistor two-watt, Flameproof Resistor voltage investigation whenever NOTE: the shunt resistor should be removed from the meter before making any voltages of 0.5 volts AC or greater measurements other than stray voltage (cow-contact measurements). are measured across cow-contact CAUTION: The shunt resistor must be removed from the meter before using points using the point-to-point the meter to measure energized conductors. measurement method described. Monitoring Stray Voltage 8

Where practical, your electric MONITORING STRAY ters with an acceptable scale are utility will identify on-farm sources VOLTAG E frequently available for less than $50. of stray voltage for you. A qualified ou should install your own Not all voltmeters are suitable electrician may be required to voltmeter in the barn and for constant exposure to the damp perform work necessary to reduce regularly monitor the level of environment found in many loca- contributions from these on-farm Y tions in a barn. You must carefully stray voltage present. Through sources. regular observation, you can quickly choose the right meter and the Your utility may also conduct an become aware of any voltage in- proper installation location. investigation using controlled, crease, possibly due to equipment or standardized test procedures to wiring shorts, which otherwise may FOR MORE INFORMATION determine to what extent electrical go unnoticed. Figure 3, below, For more information about distribution facilities or other off- indicates typical voltmeter connec- stray voltage or its detection, call farm sources are contributing to tions. your local utility for assistance. Or, stray voltage levels. If an abnormal The voltmeter should be in- call your electrical contractor or contribution is found, they will take stalled in a dry location where it can milking machine supplier. All can action to help reduce stray voltage be conveniently read during milking assist you in determining if stray levels on your farm. Even if the off- time. voltage is present, and more impor- farm contribution is found to be Accurate and easy-to-read digital tantly, how excessive levels of stray normal, some utilities may make voltmeters are available for less than voltage can be minimized. minor system modifications to help $100. Analog (needle-type) voltme- reduce stray voltage levels.

FIGURE 3: Typical Voltmeter Connections #18 Insulated Wire To Voltmeter Location

Outside Main Barn Service Wall Panel Inside Barn

Service Ground Ground Wire Rod Outside Barn

MILKING PARLOR OR STANCHION BARN SERVICE PANEL Point-to-Point Stray Voltage Measurement Point-to-Reference Ground 30 (For diagnostic purposes only.) feet Farmers’ Stray Voltage Checklist 9

This checklist will assist farmers in visually inspecting their electrical systems and noting poten- tial stray voltage sources. A check mark placed in the “yes” column indicates a potential problem. In most instances, a qualified electrician should be contacted for the repair or replacement of electrical equipment or wiring that may be needed. Yes No MAIN FARM SERVICE Connection to the ground rod - loose, corroded ...... ______Ground rod(s) missing at the service entrance ...... ______BARN SERVICE ENTRANCE Ground rod(s) missing at the service entrance ...... ______Connection to ground rod(s) - loose, corroded...... ______Large accumulation of feed dust or other debris on service box ...... ______Corroded or loose neutral connection ...... ______Panel cover missing or removed ...... ______MILKHOUSE Wires sitting in water ...... ______Electric portable heaters on bulk tank ...... ______Broken or missing bonding strap for milkline ...... ______Damaged or missing seals on electrical fixtures, switches, outlets, lights, etc...... ______Corrosion of electrical fixtures ...... ______IN THE PARLOR OR AROUND THE BARN Pulsator wiring —Pinched wires ...... ______—Loose, hanging wires, stripped screws ...... ______—Scrapes, breaks or cracks in insulation exposing the conductors ...... ______—Broken stall cocks ...... ______Wires lying in damp or wet areas ...... ______Loose, hanging wires ...... ______Broken or bent conduit Energized open wires taped or untaped and extending from ceiling or wall, not in a junction box ...... ______120-volt non-polarized or non-grounded appliances used in barn (clocks, heaters, radios, stereos, etc.) ...... ______Cow trainer insulators broken, missing, dirty or covered with whitewash ...... ______TYPICAL PROBLEMS WHICH MAY INDICATE OR RESULT IN STRAY VOLTAGE Light dimming when motors start ...... ______Lights seem too bright ...... ______Electrical shocks from any equipment ...... ______Wires, electrical boxes or motors in wet or damp areas ...... ______Frequent fuse blowing ...... ______Electric fence or cow trainer ground connected to farm electric system ground ...... ______Electric fence or cow trainer ground connected to water or milk lines or stanchions ...... ______Bent or broken conduit ...... ______Damaged wire insulation exposing conductors ...... ______Insulated wires wrapped around metal pipes ...... ______Damaged or frayed extension cords ...... ______Motors, operating irregularly under load, sparking, etc...... ______Electrical outlets not properly grounded to accept a three-prong plug ...... ______Stray Voltage Data Sheet 10

This sheet should be used to record milkhouse and barn area voltage measurements. If any of the voltages recorded in B below are greater than 1.0 volts AC, you may want to call your local utility office and request assistance in conducting a more thorough stray voltage investigation. NAME: ADDRESS: PHONE: VOLTAGE MEASUREMENTS DATE TIME A. Diagnostic Measurements (taken without 500-ohm resistor) CONTACT POINTS VO LTS VO LTS FROM TO (AC) (AC)

Bulk Tank ...... Milkhouse Floor Drain ...... ______Milk Pipeline ...... Milkhouse Floor Drain ...... ______Water Pipe ...... Milkhouse Floor Drain ...... ______Barn Entrance Panel ...... Remote Reference Ground ...... ______Water Bowl ...... Remote Reference Ground ...... ______Stanchion ...... Remote Reference Ground ...... ______

B. Stray Voltage Measurements (all measurements should be taken with and without 500-ohm resistor to make sure your electrical connections are good) Record voltages at several locations in barn while milking equipment is running. Note which equipment is running during measure- ments. 1ST MEASUREMENT 2ND MEASUREMENT COW CONTACT POINTS VOLTS (AC) VOLTS (AC) VOLTS (AC) VOLTS (AC) FROM TO (with 500-ohm resistor) (without resistor) (with 500-ohm resistor) (without resistor)

Drinking Cup ...... Floor ...... ______Stanchion ...... Floor ...... ______Waterer ...... Floor ...... ______

Drinking Cup ...... Floor ...... ______Stanchion ...... Floor ...... ______Waterer ...... Floor ...... ______

Drinking Cup ...... Floor ...... ______Stanchion ...... Floor ...... ______Waterer ...... Floor ...... ______Mission Statement 11

his publication was developed by the T Wisconsin Farm Electric Council.

The mission of the WFEC is to initiate, develop, support, and coordinate education, research, and communication programs on significant and emerging rural energy issues for the consumer, energy suppliers, and allied industries through cooperative efforts of council members.

Related Publications from the Wisconsin Farm Electric Council Farming Safely and Efficiently with Electricity Equipotential Planes for Stray Voltage Reduction Planning Electrical Systems For Dairy Expansions

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