Stray Voltage Investigation

Begin the investigation by identifying those points animals can touch, such as stanchions-to-floor, feeders-to-floor, etc. It is standard procedure to check other points if anyone reports having received shocks from a given piece of equipment, if animals appear nervous around or avoid some equipment, or if the level of voltage measured between the standard checkpoints suggests that further checking should be conducted. Both AC and DC voltages should be monitored with the milking system in both the operational and non-operational modes. In problem cases, attempts should be made to have both an electrician and a local utility representative at the site during diagnostic testing.

Warning - Identification and, particularly, diagnosis of stray voltage problems can require considerable electrical expertise. Often, the input and observations of people in daily association with a stray voltage/current problem are critically important to its solution. However, electrical systems can be dangerous. Persons without special training should never attempt investigation of the electrical distribution or farm electrical systems. Persons without special training should never open electrical service panels nor should they even contemplate altering any wiring.

Using a voltage measuring device with well insulated probes to measure voltages between possible points of animal or human contact should not result in a safety hazard with one important exception. Voltages that cause stray voltage/current problems are normally so low that they cannot be detected without special instruments. If an electrical shock can actually be felt or if animals are knocked down, a possible hazard to life exists. The device or electric circuit responsible for the shock should be disconnected by unplugging the device or by de-energizing the circuit at the service panel. The situation should be examined by an electrical professional as soon as possible.

Failure to properly diagnose the source of stray voltage problems can result in unsatisfactory, incomplete, and expensive "solutions."