Stray voltage is a natural, but often misunderstood, phenomenon that Idaho Power and other utilities have studied for the past 40 years. Idaho Power's Stray Voltage brochure (PDF, 629KB) explains why stray voltage exists and what amount is acceptable for a dairy farm, according to U.S. Department of Agriculture standards.

It is a voltage that develops on the grounded neutral system of either the farm wiring or utility distribution system. If an animal touches grounded metal equipment under the right conditions, any voltage on the neutral system will cause a small current to flow through the animal into the ground.

Multiple studies by the U.S. Department of Agriculture and other federal, state, utility and dairy organizations have found that stray voltage can be kept to levels where dairy livestock health and production are not affected. The USDA Handbook 696 (PDF, 7.4Mb) details the latest research on stray voltage. This PDF may take up to 17 minutes to download on a 56k modem. To request a paper copy of the handbook, call Idaho Power at 208-388-2316.

If you have concerns about stray voltage on your property, please contact us. Our trained stray voltage technicians will visit your property, measure the level of voltage present, and explain how to repair outdated wiring on the farm. A downloadable walk-through checklist (PDF, 47Kb) will help you inspect areas on the farm where stray voltage levels might be higher than normal.

See our frequently asked questions for more details.