Power Cord Ground

Hello,

I have had good luck using the Belden 14 awg shielded power cords to replace my stock cords. When purchasing a used amp a couple of years ago, I received a huge power cord with Hubbel hospital male/female plugs attached. This cord never sounded right to me (loss of dynamics) and I assume it may have been a home made cord. I decided to try replacing the molded ends on a spare Belden cord with the Hubbel plugs from the other cord. The Belden cord has foil shielding, three wires +,-, and ground, and another bare silver wire running between the foil and the other 3 wires. I sawed apart the molded plug from the Belden cord and the silver wire does not seem to be connected to either of the plug prongs. I assume it has something to do with shielding. My question is, what is this silver wire, and what do I do with it when I hook the Belden cord up to the Hubbel plug ends?

Thanks for your help,

Tim