Thru hull bonding

I have a head sink drain (thru hull) that is bonded to the ac outlet ground in the head. This doesn't seem right to me. All of the other thru hull's are bonded to a common copper strapping through out the boat. The thru hull on the outside of the hull is showing signs of corrosion according to my diver. Anyone?

Bonded or grounded? Does the ac outlet have another ground wire going to the panel and in turn through a galvanic isolator to the shore outlet.
Have not heard of this done before in any event.

I think there are sometime some confusion regarding bonding and grounding.Grounding is the third wire in you ac and the signal is taken back to the distribution panel. Bonding is a single wire ran from thru holes in contact with sea water, then engine,heat echangers zinc mounts ec. basicly anything that touches sea water. The two systems provide a different need. My boat has copper plates at the stern. Hoplfully someone smarter then me can provide a better tutorial .

No, that's wrong. As stated above the AC grounding conductor should be connected to the DC negative system in one place, the engine ground or a ground bus. The AC outlet should be grounded back to the AC Grounding bus. The through hull should be bonded to the rest of the through hulls and the DC negative system or a common hull anode if you have one. Somebody messed up the wiring, it needs to be fixed, both a safety hazard with the outlet (needs to be GFCI if in a head and GFCI won't work with false ground) and a corrosion issue to your through hull.

Not correct wiring. Sounds to me like someone is trying to add a ground or fool a gfi when there is no ground in the wire.
Check the wire. you probably only have 2 wires in the ac line. If so you should change to a2 prog outlet.
Pull the plug and take a pic . I can tell you what is going on then.

The bonding wire for the thru hull was placed on top of the ground wire for the outlet. The bonding wire size was 12 much smaller than the size 8 wire used on all other thru hulls. so I changed to size 8 and relocated to a more suitable location.