What Makes a PCC a PCC? The concept of a point of common
coupling may not be as simple as you think — Editorial Director
John DeDad offers some insight. And Mark McGranaghan, vice
president of Electrotek Concepts, compares sine-wave and square-
wave inverters. I've heard the term “point of common coupling”
used in discussions on harmonic distortion and seen it in
technical papers. To what does the term refer and why is it
important? DeDad's answer: The term “point of common coupling”
(PCC) gained popularity and importance after the release of IEEE
519, “Standard Practices and Requirements for Harmonic Control
in Electrical Power Systems,” which defined it as “the interface
between sources and loads on an electrical system.” The late
Warren Lewis, a true power quality pioneer, did the best job of
defining the PCC and detailing its importance. In his view, the
purpose of IEEE 519 was to help define conditions existing at
only this point on the wiring system. Most power quality
professionals originally thought th