If your question is not answered here, or if you'd like more information, please contact us. If you prefer, you can also schedule a visit from your agricultural consultant.

What is the difference between a volt and a milliamp?
Volts and milliamps are measurements of electricity. In case of stray voltage, the number of volts describes the potential (or push) for current to flow through the cow, and the number of milliamps is a measurement of this current. Since a cow has a resistance of about 500 ohms, one volt applied across the cow, from hoof to mouth, will cause two milliamps of current to flow through the cow; two volts applied across the cow will cause four milliamps of current to flow through the cow.

This follows Ohm's Law: Voltage = Current (amps) X Resistance (ohms)

Back to top

Do equipment planes reduce stray voltage?
If installed properly, an equipotential plane can reduce levels of stray voltage by keeping all surfaces that livestock touch at approximately the same electrical potential. This is done by installing a wire mesh in the floor and bonding it to the stall, water system and grounding system. Installation of an equipotential plane is highly recommended, especially when new stall barns, freestall barns and parlors are being planned.

Back to top

Is stray voltage reduced by moving the transformer out of the yard?
There is no reason to move the transformer away from livestock housing facilities. In fact, distancing the transformer can actually increase the levels of stray voltage if the customer's neutral conductor is not properly sized. When the transformer is moved away from the barn, the neutral wire is lengthened and the voltage drop on the neutral wire is increased. This voltage can show up in the cow contact area, so it is important to keep the transformer located close to the housing facilities.

Back to top

Do rubber mats prevent stray voltage?
No, not really. In most cases, rubber mats are made from recycled tires. These mats are porous and some may contain metal fragments. In addition, accumulated manure and urine can negate any insulating value the mat may add.

Back to top

Does it make sense to install a piece of plastic in the water line to reduce stray voltage?
No. Installing plastic in the water line can actually cause a dangerous situation. If a piece of equipment faults or shorts out , the fault current is better able to flow back to the source when the water line is continuous metal. This flow of fault current will trip a circuit breaker and turn off the failing equipment. A piece of plastic inserted in the water line could actually prevent the circuit breaker from tripping and create a dangerous situation in which a person or animal could be electrocuted.

Back to top

What is a neutral isolator and why is it used?
A neutral isolator is a device that is installed between the utility (primary) neutral conductor and the farm (secondary) neutral conductor, separating the two. Although a neutral isolator will reduce the effect of primary neutral voltage on the farm, it will not prevent an on-farm electrical problem from affecting the cattle.

Back to top

How much does a neutral isolator cost?
WPS customers can have a neutral isolator installed on their farm for an initial cost of $950, plus $35 tax per month. The monthly charge pays for maintenance, annual inspection and testing by WPS. Farm wiring must meet the National Electric Code before we will install the isolator. If the neutral isolator is removed before the end of the 12th month, the monthly payments will be refunded.

Back to top

What is the difference between a neutral isolator and an isolation transformer?
An isolation transformer accomplishes the same thing as a neutral isolator. This is done by separating the windings of a transformer. This option usually costs more than a neutral isolator because of the cost of the equipment installed. Also, the isolation transformer belongs to the farmer, who is responsible for maintenance in the event of lightning damage or transformer failure.

Back to top


WEC Energy Group