I installed my window air conditioner and the GFCI on the end of the cord
would not reset. I figured I would replace the plug and get an inline GFCI
to replace what was there.

I cut the plug off the end of the cord. As I was doing this I was wondering
how I would figure out which side was black and which was white. Well I
looked at the cut end and to my relief I saw a white, black and a green
conductor inside the sheath, OK a piece of cake.

As I cut back the sheath I found that the white and black wires were wrapped
with a copper shield like the outer conductor in CATV cable.

I was like what was I supposed to do with this shield. I cut it back the
"shield" to keep it away from the terminals, put the plug together plugged
into the GFCI and every thing worked.

So why the "shielding"?