Rectifier and Test Lead Spacing

[moswitch]

Is there a formula to determine the distance of pipeline that CP can protect from a single rectifier influence? Please reference the source of your response as I would like to document this process. Also is there any rule of thump as to the interval between test leads on pipelines?

 

[brimmer]

1 to 2 miles for test post spacing. Distance current will travel will depend on soil resistivity along pipeline, quantity of current required to protect the pipeline, what coating pipeline has (coating efficiency), what resistivty is at groundbed location, There is no one formula.