Heard about this from someone who attended the recent AFCOM conference (hey, where are the trip reports from those who went??). Megger has a new amp-clamp style meter that can measure an intact power cord -- no need to separate the wires. Dunno how it works, but it has a slick self-centering mechanism, which should certainly help reading accuracy and consistency. About $250.
http://www.megger.com/common/documen..._DS_en_V02.pdf
If anyone gets a chance to try one, please let us know how it works.
Ken