For Wisconsin Farms

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Alliant Energy-WP&L's Farm Wiring Program can help improve your farm's safety, productivity and efficiency, while decreasing the potential for stray voltage.

Learn more about the Wisconsin Farm Wiring Program

PSCW Regulations

The Public Service Commission of Wisconsin has defined a standardized measurement of stray voltage as "the voltage measured across a 500-ohm (nominal) resistance connected between two cow contact points."

The PSCW has also defined a "level of concern" - one volt of cow contact voltage measured as above, or two milliamperes of cow contact current. This level of concern may be contributed from both on- and off-farm sources.

Utilities companies like Alliant Energy must take corrective action if they contribute more than one milliampere, or 0.5 volts, of this total. A 500-ohm resistor is used to simulate the worst case or lowest resistance of the animal circuit.

Docket 106

Regulatory proceedings conducted by the Public Service Commission of Wisconsin first investigated stray voltage in 1987. Their investigation culminated in an order issued in Docket 04-EI-106 on January 18, 1988. Amended and supplemental orders were made in 1990.

The orders describe stray voltage investigative procedures, the level of animal contact current at which electric providers must take corrective action and the responsibility utilities must assume.

Docket 115

In 1996, following extensive public hearings and testimony on the results of stray voltage research, the PSCW released Docket 05-EI-115. This docket further defined the issue and outlined the appropriate utility response.

Among other order points, Docket 115 states that neutral isolators installed to mitigate off-farm stray voltage must be removed within 90 days of installation and that the source of the problem must be corrected within that period of time.

If, for some reason, the isolator remains in place after 90 days, the on-farm wiring must be brought up to National Electrical Code standards.

Docket 115 also requires increased standardization of stray voltage investigation protocols, data recording time and reporting requirements.

Wisconsin statistics

Data compiled by the Public Service Commission of Wisconsin from investigations of 1000 Wisconsin farms indicate that:

• Of the cases where the contribution from the primary distribution system to cow contact current was more than one milliampere, 69 percent were served by an electrical cooperative and 23 percent were served by an investor-owned utility.
• Of those cases where the contribution from on-farm sources was greater than one milliampere, 62 percent were associated with investor-owned utilities and 31 percent were associated with electric cooperatives.
• Slightly less than 30 percent of the farms investigated had stray voltage levels of one milliampere or greater.

Alliant Energy serves approximately 20 percent of Wisconsin's dairy farms. Data from 2,431 Alliant Energy stray voltage investigations show:

• Animal contact current levels of one milliampere or more were found on 45 percent of dairy farms investigated.
• On farms where more than one milliampere of animal contact current was found, the primary system was the cause of 56 percent of those occurrences.