Detecting and Understanding Stray Voltage
All stray voltage is unintentional and undesirable, yet it is extremely common. In fact, it would be rare to find a farm or home without it, usually not in a good location. The main culprit, even though there are several variations of causation, is that with all standard 120 volt wiring we only have one hot wire, one neutral wire and a ground wire.
If the neutral wire is inadequate or if there is a weak or failed connection, the electrical current arriving on the hot wire must return to the source in some manner, which means it will try to go through any and all other objects that will conduct electricity. This undesirable flow of electrons can be via the earth, metal buildings, metal stanchions, fences or other objects.
The motor on a center pivot irrigation tower had been experiencing a tiny short in the wiring recently on a Midwestern farm. It had been this way for several weeks, but it was still working, and as you know there’s never enough time to do everything on the farm. However, the sand filter on the irrigator was also full, and this function needed emptying. The farmer was up on a metal ladder opening the overflowing trap to clean it out. It was safe, because all the pumps were switched off — except for what he did next, which was to instruct his wife to turn on the pump in order to flush the sand. It was a fatal mistake, as 480 volts surged through the system, instantly killing the farmer.
Another farmer had a grinder in the shop with a minor short in the motor; when it was turned on, it would give out a little shock. He “cured” the problem by turning on the grinder switch with a wooden broomstick. Who hasn’t done something like that?
On another farm there was a series of five livestock water fountains all connected to the electrical line. The first four fountains seemed normal, and the cattle were approaching them casually and drinking water normally. However, the cattle seemed to sense something was wrong with the fifth fountain, and they avoided it. Thirsty, two young heifers approached the fifth fountain, which was also overflowing slightly and creating a small puddle they were standing in. Within seconds after touching the water in the fountain, both heifers were instantly killed.
I heard many stories like this from Jerry Lush, a professional stray voltage consultant and ag engineer from Sioux Falls. After decades in the field of electrical energy, Lush can recount many horror stories of the abundant, and usually safe, power supply that we can’t seem to live without. Even folks who do not allow commercial electricity on their farm can encounter problems. I’m talking about stray voltage, a potential evader that can sneak onto any farm or barn.
What is Stray Voltage?
This is a very aptly named problem, in that it applies to any two objects that have electrical potential between them that ideally should not have any voltage difference between them. How much does it take? In general, we are always hoping for zero voltage, however, almost any animal can easily feel anything at 0.5 volts or higher. We could feel it too, but we usually have shoes or boots on and sometimes gloves. Lush says he finds this all too often and has even seen it run as high as 9 volts of current. Just imagine touching your tongue to a 9 volt battery.
Spark Your Electrical Vocabulary
Amperage: A measurement of the amount (strength) of current that is flowing through a wire.
Current: As stated above, current (flow of electricity) is measured in amps.
Induced voltage: A form of stray voltage that comes from other nearby circuits. This is more difficult to diagnose, but commonly runs through head stanchions or milk lines. It can be diagnosed and cured by a professional.
Resistance: This is something like a heater or light bulb; it is anything that holds back the current. It is measured in ohms.
Single-phase wiring: Brings 120-240 volts via one to two hot wires.
Three-phase wiring: (High voltage for large motors) brings in three hot lines.
Voltage: A unit of measurement of the pressure that pushes the amps through the wire.
Wattage: The sum of volts X amps and equal to power, as in the horsepower of an electric motor, for example. High voltage lines can adjust current flow by vastly increasing the voltage, which simultaneously lowers the flow of current and reduces line loss. Many transmission lines carry 7200 volts (this is what linemen work with) whereas coast-to-coast lines can carry 35,000 volts or more.
Potentially dangerous stray voltage was just diagnosed in our own home because the neutral wire coming from some “professionally installed” wiring, which had been put into our house by licensed electricians during remodeling, had actually been spliced into the ancient knob-and-tube neutral wire that runs through most of the walls and ceilings.
Jerry Lush has nearly 40 years of experience in the field of electrical energy.
Lush states that a big part of the problem is that electricians and linemen may see electricity in a different way than engineers trained in electricity (I’m generalizing here; there are some very knowledgeable technicians, likewise engineers are frequently so specialized they just don’t know everything, some engineers have no electrical training at all). But typically, the linemen have not been trained in household or farm wiring. Sometimes they can barely visualize the flow at all; their job is to get the power to the site.
Electrical engineers, including agricultural engineers, are trained to see electrical current wherever it is, quite like the rest of us might see water flowing. We could hardly expect to see water flowing into a structure without knowing where and how this water will exit. With voltage, if the neutral wire is not fat enough, or if the distance is too far, there’s no way it can keep up with electrical flow so that current “spills” into other areas in order for it to eventually get back to the source.
Stray voltage can come from any electrical device that is malfunctioning. Even properly installed wiring or devices can be damaged by moisture, lightning, or mice, squirrels and rats. Most commonly afflicted are barn fans in the summer and water tank heaters in the winter. Lastly, there can often be problems coming onto your farm from the utility service. Wherever the source, proper diagnosis is a critical starting point.
Symptoms of Stray Voltage
The key word is mysterious. Many farmers think they must be bad farmers or bad managers, or that they must have poor-quality livestock, not realizing there is a hidden cause. Electricity is essentially invisible, and we are usually focused on visible issues. Every single farm, ranch barn, garage or home can have stray voltage problems — we have seen it with dairy, beef, swine, sheep, goats, poultry or horses, but most often electrical problems are most clear in a dairy. In general, dairy animals drink more (to make milk), and they are quite often indoors and being handled, in a place where we can watch them.
Animals that are plagued with stray voltage will most frequently manifest specific problems such as mastitis, or high somatic cell count (pus in the milk), or they are jumpy when they come in to be milked. In many cases they just will not let down their milk flow. Watch your animals when they drink; they will tell you. Frequently they will only drink just enough to satisfy their thirst but not enough to maintain adequate production, which soon falls off even worse. Instead of taking a steady intake of water, they merely lap at the water, bobbing their heads.
Humans are more likely to feel the voltage themselves when walking barefoot on wet concrete, even more so when touching plumbing or metal when they are somewhat grounded by being wet. People have even been known to keep a dry rag around so that they can shut off their shower faucet without getting a mild shock.
Diagnosing Stray Voltage
Ideally, hire a pro! Lush is one of several in the United States. He comes by his skills honestly with two degrees in ag engineering and years of service working for rural electric utilities and co-op extension services. He has focused exclusively on stray voltage problems since 2007. Having worked both for the utility and for the farmer, he understands both sources of problems. He says his main tool of the trade is a simple volt meter, one that can measure micro voltage. At times he will hold a metal rod in one hand as he explores with the leads from a volt meter. He also uses a device that converts electrical current into an audible signal which emits a buzz if there is current flow. Quite often he can instantly spot wiring design errors or find loose connections. By the use of all these devices he can pinpoint sources of the problem.
Electric fencing is rarely a problem, in general, but if wired wrong it can be devastating. Lush says that it is of utmost importance to create a grounding system that is as good as or better than that of the rest of the farm. The fence should have its own individual ground and it should never be attached to any other ground. Place the ground far away from barns or other electrical systems.
Can Stray Voltage Be Cured?
Absolutely! However, Lush admits there are a few mysterious challenges over a lifetime of work. He recalls a few farms that defy logic such as an Amish farm he once investigated that haunts him. They were having barn issues of serious stray voltage in the metal stanchions yet were hundreds of yards from power lines, buried lines, transformers or substations. In some of these cases, even though no source can be detected, the professionals can build a circular passageway around the farm buildings using highly conductive materials.
Most of the time however, he says he can diagnose and cure almost every farm within four hours’ time, and most diagnoses come in the first half hour. Even if the problem is coming from the utility, a power pole/transformer neutral isolator can be installed. Since many problems come from inadequate grounding, this is a cure that can be rewired in a proper manner and without much cost. With 240 volt wiring there are fewer problems because there are two hot wires, and the current will arrive via one hot line and go back to the source via the other hot wire.
However, it’s not always that easy to settle disputes if questions arise with regard to the sources of the problem. If the utility will not accept responsibility for causing the problem or for the cost of fixing it, many farmers can feel left in the lurch. In fact, many institutions practically deny the existence of the problem, some even insinuating that the farmer must either be crazy or just a whiner.
Here in my state of Minnesota alone there are currently at least six pending lawsuits between farmers and the utilities with little hope of resolution in sight. However, the tide is slowly beginning to shift toward more accountability and more willingness to admit that the problem exists. Is it worth fighting? One dairy farmer in Minnesota suing the power utility estimates the voltage running through his dairy cost him over $700,000 in lost production, last year alone. Another Minnesota suit was settled, awarding $3 million to the damaged parties.