This paper draws out a set of characteristics that indicates collapse of a transmission or a distribution line. To do this task, a Trapezoid shaped phasor diagram is drawn. This diagram facilitates deriving a relation that expresses the change in voltage phase angle across the line as a function of the angles of the load and transmission line impedance (condition #4). Thereafter, the progression of voltage magnitude across a transmission line is expressed in terms of the change in the voltage angle across the transmission line (condition #5).