Any Ac Power Grounds are separate from Shield Grounding, and should never share the same connection points
For the shields to have any use at all they need to be clamped to the Ground Plane at Both Ends, Signal shielded wires in some cases can be Grounded (Clamped) at the source end, if you were to have any interference problems
A P-Clip is one of the best ways to clamp a Shield to the Ground Plane, this needs to be a tight clamp when fastened
Here are some snips of how it should be done