Residential pier wiring

[desllc04]

Asking what the significance is of having an insulated grounding conductor in the wiring scheme for a pier. Folks are using 6/3 UF cable as a feed from the house to the panel at the head of the pier and then PVC conduit and THWN conductors from that panel to the end of the pier which is where the power feeds the convenient outlets and power to the boat lift.

 

[augie47]

I wonder how often that requirement is overlooked on residential pier wiring