Shore Power (The saga continues)

[TravisTraverser]

After all the input I received from my last post about shore power, I now have another mystery(for me).<br />After verifying that i can get power to my boat(used a nieghbors shore power outlet)and that it runs at least 15amps worth of equipment, I decided to be ultra safe and installed a new electric line from the house to the shore and then installed a GFCI outlet at the shore. When I plug an appliance into the outlet, it works fine, when I plug a 150ft cord into it and plug an appliance into that, it works fine, but as soon as I connect to the boat, it trips the GFCI as soon as any load is placed on it. What is strange is that I can plug into another NON GFCI on shore and everything will work.<br />I am concerned that if I do not use a GFCI that there will always be the possibility of some sort of accident, with the risk of electrocution.<br />Is it possible that the GFCI is too sensitive and does anyone know if they make other less sensitive models of GFCI's. Or am I just doing something contrary to ship to shore wiring principles?<br />I am abut ready to throw in the towel and hire an electrician, but thought I would give it one more try.<br />Thanks

 

[18rabbit]

Re: Shore Power (The saga continues)

GFCI, Ground Fault Circuit Interrupt, is sensing the presents of current on the ‘hot’ and on the ‘neutral’ lines. If either one loses current, it breaks the hot line. The test button on a GFCI does nothing more than to make contact (a short) between the hot and the safety ground, creating a situation where there will be current on the hot but not the neutral; the the GFCI should break. You do not want to de-sensitize GFCI, kind of defeats its purpose.<br /><br />The thinking behind GFCI is if you are being electrocuted, there will be current on the incoming hot but not on the returning neutral line because the your body has replaced the neutral line’s path to ground.<br /><br />I suggest you go back and re-read the responses in your original query. As I recall, there were question that were asked but never answered. There was also the suggestion that your electrical problems extended beyond just the shore power polarity. Electricity has a certain safety issue associated with it. I, for one, am reluctant to help someone that will not respond to simple questions that will facilitate a safe diagnosis and safe repair of an electrical problem. 120vac is serious stuff on a boat and can be extremely unforgiving when things go wrong.

 

[TravisTraverser]

Re: Shore Power (The saga continues)

I did check on the issues that were previuosly raised: The ground was not routed through the main breaker, there is a galvanic isolator; it is 120v 30amp circuit; which is the main breaker rating. No corrosion of any wiring is present; when plugging into a standard 3 prong grounded circuit on shore, everything works and the outlets all show 2 lights indicating "correct" on the outlet tester that I purchased. I checked the outlets with a voltmeter as explained and it came up with 120v.( red lead in small hole, black lead in either large hole or round hole shows 120v) I purchased a GFCI tester and it too indicates all is wired properly.<br />The GFCI receptacles on the boat all trip when "tested". <br />All the electrical equipment is manufacturers original, no changes appear to have been made and all the breakers including the main breaker are same manufacturer, design, color, etc. <br />So far I can get everything to work if I am plugged into to anything other than a GFCI and I realize that this is not acceptable; so far I am still in the discovery stage.

 

[Dan Both]

Re: Shore Power (The saga continues)

The tripping GFCI might be pointing out an actual ground fault in your boat, the GFCI outlets on your boat will only trip if there is a problem downstream from them (basically what ever is plugged in) you may have a neutral line that is routed to ground this would cause a load in the system to trip a GFCI.<br />You might try to isolate the problem by switching off all the breakers, plugging into the shore GFCI outlet and testing the circuits one at a time, although this will not isolate a neutral to ground fault since the neutral circuit isn't isolated by the breaker.<br />Be careful, electricity and water are a bad combination.<br />Dan