The term “stray voltage” or “tickle voltage” has been used during the last 50 years to describe the existence of voltage between two objects that should not, under normal circumstances, have any voltage difference between them. This phenomenon may develop on the grounded neutral system of a property’s electrical system and can migrate to adjacent properties through any electrical conductive utility, such as an electric, water, gas, sewer or communications system.
Infrequently, you may experience this as an electrical tingle when the electrical system in your home or your neighbor’s home has been compromised. Yet, because of the characteristics of your body structure, this condition often can exist in your surroundings and you won’t feel it.
Interestingly, some animals react to voltages too low for people to notice. Both hogs and cattle are especially sensitive to the mild electric shock caused by stray voltage, which can lead to the discomfort of the animals in their confinement areas. These occurrences have been documented to cause low animal birthrates, stillborn fetuses and many other behavioral and health issues, such as the refusal to eat, drink or procreate. The reduced production performance caused, for example, by a decrease in milk production or the refusal to eat not only diminishes a farmer’s income but also affects you at the grocery store through increased food costs.
A change in an animal’s behavior usually is the first sign of stray voltage. Some visual effects to look for include:
- Reduced water consumption or food intake – lapping water instead of drinking normally or a layer of feed in a steel trough.
- Animals agitated around feeders, waterers or stanchions – an abnormal amount of bellowing of cattle or squealing of hogs.
- Hesitation or refusal to enter areas where a shock previously was experienced.
- Excessive kicking or defecation when confined.
What’s the culprit? Farms usually consist of several buildings built over an extended period of years – each with an electrical system installed for the needs of its time. This means every farm probably has a unique combination of electrical equipment and wiring.
Obviously, today’s wiring standards and methods of operation wouldn’t have been considered when a storage building was built on the far corner of the property 50 years ago. Now, as the old wiring and equipment fall into disrepair, they could be causing occurrences of high levels of stray voltage. For example, a mouse-chewed conductor in that old storage building couldbe causing stray voltage in the entire system.
Low levels of AC voltage on the grounded conductors of a farm wiring system are a normal and sometimes unavoidable consequence of operating electrical farm equipment. The most common and troublesome stray voltage is caused by currents that normally flow through the neutral wire of an electrical circuit.
Some of the sources are:
- The bonding of the neutral and equipment-grounding conductor at multiple points in the electrical system.
- Undersized neutral conductors or the lack of properly sized equipment grounding conductors.
- Installation of equipment that is not designed for wet, dusty or corrosive conditions.
- Incorrectly wired electrical components such as motors, starters and transformers.
- High-resistance connections caused by loose or broken grounding connections.
- Poor maintenance of electrical equipment – allowing boxes, fittings or devices to get wet, dirty,dusty or damaged.
- Aged and/or defective equipment. (Some old-style motors actually use the motor frame as a conductor.)
- Voltage drop caused by excessivelylong wiring runs.
Here’s the solution. Since each farm has its own intricate electrical system, the detection of a stray voltage source and its remedy can be a very complex undertaking. No single solution will solve all stray voltage problems; in addition, you may find that the animals’ problems stem from other causes – or even that the source of the problem could be originating from an improper electrical installation on a neighbor’s property.
To eliminate possible problems, ensure that:
- Proper grounding is provided at each transformer and service.
- Neutral conductors are not used as grounding or bonding conductors.
- Defective equipment and wiring are replaced to eliminate small faults that don’t blow fuses or trip breakers.
- 120-volt loads are properly balanced to minimize neutral current.
- All conductive surfaces are properly bonded to the service-grounding conductor.
- Motors and equipment are operated at 240 volts, whenever possible, to eliminate neutral currents.
- Plastic waterers and feeders are used to minimize conductive surfaces.
- Gradient ramps are installed at building entrances and/or gradient planes are installed around feeders and waterers.
Before making a large investment in attempting to solve a stray voltage problem, have your farm’s entire electrical system analyzed by a qualified professional who has documented experience in successful stray voltage mitigation. If control devices are suggested, work with your electric cooperative and the local electrical inspector to ensure a quality installation.
