Do power companies follow a standard method or rule, as to which transformer in a 3p open delta center tapped (wild leg) is to be on the leading phase of the two (120 degrees ahead) and which is always on the lagging phase (120 degrees behind)? Something like "The wild leg transformer shall be on the lagging phase of the 2 high voltage primary supply lines, as compared to the line the main transformer (the one with the grounded center-tap) is fed by". Or is it essentially random?
