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Old 06-12-2016, 09:04 AM   #21
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Correct, a switch in the green grounding conductor is not only unnecessary, it is unsafe. There can be no switch in the green wire per code and standards.
I think I was not clear. My green between the shore power and the buss is not switched.
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Old 06-12-2016, 09:08 AM   #22
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The reluctance to induce even minor ac current is to keep down the chance of electrocuting a swimmer , and not add a corrosive load to any underwater metal.
Yes this is exactly what I was trying to address, but now I see how grounding the neutral at the generator accomplishes the same thing.

Again thanks to all, I was not trying to be defensive or pigheaded, just wanted to really understand both the how and why.
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Old 06-12-2016, 10:22 AM   #23
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So the main issue is safety regarding shore power. Only remedy is to become self sufficient with on board power sources only. Hopefully the decreased cost and increased efficiency of solar and wind will make the cord obsolete. Does ELCI mitigate the problem of current imbalance in the shore power connection?
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Old 06-12-2016, 10:57 AM   #24
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Yes, the ELCI is there to react to fault current. On older boats, there is more likely to be some small low level leakage. This is causing some heart burn with older boats in newer slips. In some marinas they have a test station where you must report in and test your electrical system before you are assigned a slip.


From ABYC:"11.4.11 Equipment Leakage Circuit Interrupter (ELCI)
a residual current device (RCD) which detects equipment ground fault leakage current and disconnects all ungrounded (110 V & 240 V) and grounded (110 V neutral) current carrying conductors from the supply source at a preset trip threshold."
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Old 06-12-2016, 11:02 AM   #25
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Regarding solar and wind. There is a new and recently patented technology which is not quite ready for market that will make solar panels less expensive and yet epresents a significant emprovement in efficiency. We expect to see this new material commercialized within a year of so.

Regarding wind. Wind power does not generate very much until the wind gets up to about 25. At that point most people are moving to a more protected anchorage. As Nigel Calder says:"Wind is a good option, only after every square inch of your boat is covered with solar panels."
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Old 06-12-2016, 11:49 AM   #26
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Originally Posted by tadhana View Post
Yes, the ELCI is there to react to fault current. On older boats, there is more likely to be some small low level leakage. This is causing some heart burn with older boats in newer slips. In some marinas they have a test station where you must report in and test your electrical system before you are assigned a slip.


From ABYC:"11.4.11 Equipment Leakage Circuit Interrupter (ELCI)
a residual current device (RCD) which detects equipment ground fault leakage current and disconnects all ungrounded (110 V & 240 V) and grounded (110 V neutral) current carrying conductors from the supply source at a preset trip threshold."
not sure if you or I misunderstood Mike66's question...I took it to mean the imbalance on hot legs of a 50 amp cord....ie...2 busses onboard not drawing exactly the same which would be near impossible.....or I wonder if he meant just leakage?
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Old 06-12-2016, 05:30 PM   #27
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I meant just leakage. Trying to comply with standards without killing anyone, especially someone in the water..
Thread drift, I guess.
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Old 06-12-2016, 05:50 PM   #28
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"Very clear explanation. I don't understand the op's reluctance to have the gen green ground wire permanently wired to ship's ground as the standards call for."

Ground wires , are connected to neutral wires .

Neutral wired carry some current esp in a 120v setup split from a 240v source (USA) .

The reluctance to induce even minor ac current is to keep down the chance of electrocuting a swimmer , and not add a corrosive load to any underwater metal.
All the current flowing in on a black wire 120vac must cycle back, return on the white wire. If there is ANY current flowing on the ground safety wire, it would trip a GFCI, so that is not good to have current flowing off the white and black wires.

GFCI and ELCI will sense the difference and turn off the power.

I have a tight AC system, I can run a GFCI on the 30 amp twin inlets, but I dont. Only the microwave and all the outlets are on GFCI.

IMO,FWIW, It is a good idea to have a tight system that does not exceed that 5 milliamp level of current leakage. ELCI is 30 milliamps. I dont have these nuisance trips people talk of on boats when using a GFCI on the shore line.

And the shore power pedestal should be the required location of GFCI or ELCI not on the boat. Is that not how Europe does it?

I have had shore power cords get damaged by whacking, getting pinched accidently, I suppose between boat and dock, and then leak current into the water. An ELCI on the boat wont help that at all. That cord, when I cut it open, had dissolved into the water 6 feet of copper wire, and was hot. A small hole existed in the yellow vinyl cover. Stuff happens that you do not expect..
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Old 06-12-2016, 09:38 PM   #29
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SDowney717, Congratulations on having an electrically tight boat. My testing reveals that most boats are tight, but it the ones that are not that have caused serious problems. ABYC now requires an ELCI on the boat's power inlet for new construction. This will hopefully help. But the NEC now requires it on marina dock feeds.The NEC (National Electrical Code) "NEC 555.3 Ground-Fault Protection. The main over-current protective device that feeds the marina shall have ground fault protection not exceeding 100mA. Groundfault protection of each individual branch or feeder circuit shall be permitted as a suitable alternative."

My comment regarding ELCI was related to these two new requirements. The NEC requirement has caused some great problems at some new marinas. Ocracoke NC had a lot of trouble when the new docks opened a year or so ago. In Ft. Pierce this winter, before you were assigned a slip in the new section of the marina you had to go to a test dock and plug into a test outlet to be sure you had no ac electrical leakage. These are probably just early adopter problems, but the ELCI may actually drive people with older boats to make the necessary repairs and upgrades to prevent AC leakage into the water.
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Old 06-14-2016, 08:45 PM   #30
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SDowney717, Congratulations on having an electrically tight boat. My testing reveals that most boats are tight, but it the ones that are not that have caused serious problems. ABYC now requires an ELCI on the boat's power inlet for new construction. This will hopefully help. But the NEC now requires it on marina dock feeds.The NEC (National Electrical Code) "NEC 555.3 Ground-Fault Protection. The main over-current protective device that feeds the marina shall have ground fault protection not exceeding 100mA. Groundfault protection of each individual branch or feeder circuit shall be permitted as a suitable alternative."

My comment regarding ELCI was related to these two new requirements. The NEC requirement has caused some great problems at some new marinas. Ocracoke NC had a lot of trouble when the new docks opened a year or so ago. In Ft. Pierce this winter, before you were assigned a slip in the new section of the marina you had to go to a test dock and plug into a test outlet to be sure you had no ac electrical leakage. These are probably just early adopter problems, but the ELCI may actually drive people with older boats to make the necessary repairs and upgrades to prevent AC leakage into the water.
Keeping the electrical system sealed and dry goes a long ways on keeping it tight regarding leakage. And the appliances too need to be in good shape. I thought about that and actually can unplug two branch circuits going to places that can get wet. Just a plug socket in a dry spot, so pull the plug and it disconnects that wire, cheap and easy.
Another way is use a 2 pole switch or just turn off the breaker.

Interesting that 100 milliamp level. What will happen is if 10 boats plug in downstream to that feeder and they had 10 milliamp each of leakage, that tenth boat will trip off power to everyone on that dock. I can see that is not a great solution, but does save the marina the cost of installing individual ELCI devices on every power pedestal.
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Old 06-14-2016, 08:54 PM   #31
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Your analysis is spot on and it is exactly what was happening when this first went into effect. The marinas have gone toward putting the protection at the individual outlets. More expensive in the short run but better customer reviews.
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