[MrFixr55]

+1 on Gary, Ron R and others. The reason that the shield is grounded on one side only is to prevent ground loops (the shield acting like the secondary of a transformer).

We often specified a "wired ground" instead of using the conduit as a ground in some of our analyzer installations (These systems were sensitive to poor grounds). To prevent aggravation by ground loops, an "isolated ground" outlet was used where the ground pin was not connected to the outlet frame. This way, a solid, quiet ground could be obtained (assuming that the subpanel was quiet.