I believe that's where a LOT of people have a problem, as in DC electrical a black wire used to denote a "ground". In AC electrical, black is the color for a "HOT" wire, which carries the current. The AC "neutral" wire is white in color and carries the same current as the hot wire. As long as the current remains in this closed black/white wire circuit there is no danger, but if it should escape (a “fault” or “short circuit”), it will attempt to go directly to ground.dcunniff":3n8176so said:The 110V and 12V grounds come together ...
dcunniff":28e1ljdc said:Here's a paragraph on AC and DC wiring tied together and a description of galvanic action, from P&G Web Consulting.
Galvanic activity normally restricted to one boat can extend to affect other boats via the AC green grounding wire when ever two or more boats are plugged into shore-power. This is because the boat ground (including the bonding wire) and the AC green wire are connected together at a "common ground point" (often the engine), completing a circuit between multiple boats. Typically, the galvanic current passes from one boat's underwater fittings through a bonding wire inside the boat, onto the common ground point, onto the AC green wire that passes out to the shorepower chord to the dock pedestal, onto another boat's pedestal, power chord, boat, common ground, bonding wire, fitting, and then back through the water to complete the circuit. The boat with the least noble metal among the different boats will always protect the others (see figure 2).
Here's info from Marineco about an AC electrical guide. http://www.marinco.com/docs/guides/Boat ... trical.pdf. Note that if you have a problem with an AC ground on a boat and you aren't connected to the boat's DC ground you can be zapped.
Note on pg 19 for a standard 110V AC shorepower system an isolator is optional. I added my Newmar galvanic isolator today.
Here are some photos of it (cutting the AC green wire and running it in and out of the isolator and then up to the breaker panel).
dcunniff":1zaid4cc said:Capt. Ronnie, I didn't research it hard on price.
I ordered it from Consumer Marine Electronics for the first time. They are in NJ. I got it in about 3 days. I paid $149 plus $6 shipping. This was for the 30 amp model, GI-30. Consumer Marine's website is www.consumersmarine.com.
West Marine carries the more expensive Guest models. They are ignition protected and can be hooked up to an optional display.
What photos are you interested in.