While conducting overline surveys including Close Interval Survey (CIS), Alternating Current Voltage Gradient (ACVG), Direct Current Voltage Gradient (DCVG), Alternating Current Current Attenuation (ACCA) and Depth of Cover (DoC) in the Southeast Saskatchewan, Canada, a section of the cross Canada/US border Alliance pipeline, an unexpected CIS potential was encountered whereby potential measurements dipped, falling below the -850mV potential criteria, before rising again back into the range before the drop. The location of the potential drop occurred at a foreign crossing thus stray current was initially suspected. The field crew remained nearby while the foreign crossing owner representatives were notified of a possible interaction requiring further investigation. An interruption and influence analysis plan was put together to determine the nature of the influence on the Alliance DC Potential measurement circuit. This paper summarizes the preliminary analysis and test plan, the field measurements, and results.