Generator Question

[True Story]

Thanks for the confirmation Joe.

[Sea Wolf]

The first article Tom refers to is very clear it it's initial summary and so well done that I'm going to post an exerpt here:

Research has been ongoing to determine why people are drowning due to electric shock in freshwater marinas across the nation. In addition to those occurrences where people are known to have been shocked, more drownings may indeed be caused by electric shock than are reported because autopsy results are not able to pinpoint this as the cause.

The freshwater environment is of most concern since salt water's high conductivity allows the majority of ground fault currents to pass harmlessly to the earth ground (this has been previously quantified through a significant amount of research in saltwater). In freshwater, where electrical resistance is high, a person's body represents the low resistance path that the current is seeking to return to ground. Hence, the occurrence of deadly electric shocks to immersed people in freshwater marinas, and none being reported in saltwater.

This research will substantiate the need to monitor the electrical condition of a marina using available marina monitoring tools to reduce the chances for personal injury and death from electrical shock induced by electrical faults in boats and marina electrical systems.

An opportunity recently became available to conduct electrical testing in a large, well-maintained marina facility located on a freshwater reservoir in the southeastern United States. The summary of this freshwater research is presented below. It will demonstrate the following:

A low-level ground fault (less than shore breaker trip setting) can be induced on a boat connected to shore power.

If the dock ground system is in good condition, the induced ground fault current will be safely carried off the boat to the earth ground ashore through the dock ground wiring system, therefore preventing lethal potentials from appearing on underwater gear.

If the ground system is disabled (to simulate a faulty ground system) while the ground fault is being induced, a portion of the fault current will still find it's way to the earth ground directly through the boat's grounded underwater equipment (e.g. stern drives, propellers, shafts, struts, rudders, etc.) and the water.

The fault current traveling through the water sets up an electrical field that is potentially lethal to any person encountering it.

And here's the summary from the second:

Low level ground fault leakage in the marina AC shore power system can cause lethal potentials to appear on any metal surface – either on a boat or on the dock. In fresh water the electric field surrounding this surface can paralyze a swimmer. There is no warning that this condition exists, and it has resulted in numerous drownings. Further, there is no post-mortem evidence that electric shock was the cause. Therefore, the fatalities listed below are only the known electric shock caused drownings, which were investigated because of circumstantial evidence, i.e., multiple deaths, eye witnesses, considerable distress, cries for help, shock sensation reported by rescuers, etc.

We do not know the exact wiring errors or ground faults that created some of the incidents listed below, but it can be assumed that an energized AC lead (L 1 ) came in contact with a bonded (grounded) object, and coincidently, this object was not connected to the shore bonding (grounding) system. This caused a voltage to appear on bonded under-water metal gear, setting up a lethal field around the boat. This was true in every case that was investigated.

_____________________________________________________________

And that is why the NEMA wring standards require that the ground of the AC shore power be grounded to the negative side of the boat's 12-v electrical system, which will

1. Eliminate the current through the water as the stray/shorted current goes back out ground wire.
2. Hopefully also open either the GFI and / or amperage limiting pretection devices in the boat.

I think I'll go ahead and connect the two together by inserting a 3-prong to two prong electrical wall outlet adapter (little grey guy) into the bus bar and connecting the third wire (green, ground) from it to the boat's negative side.


*************AND THAT'S THE SHOCKING TRUTH!!!*************

Joe.

[Byrdman]

WOW....so ...other than throwing in someone else, how can we test our waters at our marinas for this...."loose current field?"

And, do we need to stick some type of instument in the water around all the boats or if not, how far appart do we check the areas?

Have any of you seen those fish shaped sacrafice chunks?... where can they be purchased? My thoughts are if there is one or two of those floating in and around my lower units...then the units sacrifical parts should last longer too.

[Stimpys Dad]

SEAWOLF,
THANK YOU FOR POSTING THE INFORMATION ON THE POTENTIAL DANGERS OF IMPROPPERLY GROUNDED SHORE POWER IN FRESH WATER. I HAS CAUSED ME TO DO SOME SERIOUS THINKING. I NORMALLY CARRY A GOOD QUALITY VOLT OHM METER ON THE STIMPY AND I THINK THAT I AM GOING TO RIG UP A TESTING PROBE WITH A NON CONDUCTIVE HANDLE THAT I CAN ATTACH TO THIS METER JUST SO THAT I CAN "TEST THE WATER AT MARINAS THAT WE TIE UP AT.
REGARDS, DOUG CRUICKSHANK AKA ""THE STIMPSTER"

[Sea Wolf]

Patrick (Byrdman) and Doug (Stimpster)-

Well, I don't exactly recommend throwing in your favorite, loyal bird dog to test the waters!

Doug's right on target with the test probe made up of the voltmeter with an insulated metal probe on one end and a clip on the other to check for currents around the boat. Be sure the wires are insulated (except on the probe) for safety.

Attach the clip to the ground on the 120 v Shore Power outlet for starters. Be sure to try all around the dock / berth area around your boat to be able to get into any current path that might be there.

Don't forget to set the voltmeter on AC and the correct range.

I'd also test the Shore Power ground against the boat's negative 12 v side, which should be grounded. This will test whether it is or not. Should read 0 volts if the grounding is done right.

Then test the hot side of the 120 v system (usually the black wire) against the common wire (white / return circuit) in the boat. Should register the same full voltage available at the Shore Power outlet. Less and you have a weak connection somewhere.

Another test would be to test the GFI circuit. Set the voltmeter on amps, momentarily contacting it between the hot and the ground wires. Should pop the GFI circuit, but probably not the amperage overload circuit, as the current will be short lived. You may well blow out the protector fuse in the voltmeter, but fixing that is a lot easier than doing this procedure with a solid wire that could carry many amps and melt in and burn your hands!

Finally, you could place the meter between the insulated probe in the water and the grounded 12 volt (negative) side. Voltage here would indicate a hot wire leak somewhere between another nearby object and your grounded boat. Corrosion will be the result of any current between your grounded boat and the water around it.

Probably are other thnings to check and ways to do it, but this is just a logically derived list of places to start.

Be sure the insulated probe isn't just a wet broom stick. A cheap section of PVC sprinkler pipe would work nicely. No barefoot or wet shoes stuff, either!

None of these tests are recommended for those w/o a pretty good understanding of electricity. If you don't really understand this stuff, you won't be able to interpert the results, either.

Get a qualified electrician if you suspect a problem.

The foregoing is offered for discussion and to the best of my knowledge, but I accept no personal responsibility for any use you make of it.

Have fun, it's an eletryfying subject!

Joe.

[dogon dory]

Sorry, Folks - Post Deleted By Author

[Sea Wolf]

Dan-

It's just an easy one for me! Anything missing, incorrect?

Joe.

[dogon dory]

Sorry, Folks - Post Deleted By Author

[capneo]

Lots of good info! I'm a self employed electrician and future cd owner (I hope!) and I thought I'd chime in briefly. First, it has been my experience that GFCI, or GFI (ground fault circuit interrupter)s are extremely sensitive, meaning they will "trip" (not let electricity through) very easily when almost any electricity is going down the wrong path (ground), which is what you want it to do!
Thinking of electricity through wires like water through pipes can be helpful. If you had a sink, the faucet would bring in the water, like a wire supplies power (the "hot" wire, usually black in 120volt systems). The drain is the outgoing path, which is like a "neutral" wire (white). The emergency or overflow drain in a sink is like the ground wire (green). When a GFI measures any flow into the ground path, which you or a swimmer might be touching (instead of from the hot to the neutral, as usual) it disconnects, or turns off the faucet, and it does it FAST so nobody gets zapped. I believe that GFIs were invented at least partly because people would get fried when their radio or hair drier or whatever would fall into the bath tub. That is why they are mainly required in bathrooms and kitchens (near water sources).
The GFI outlet strip is a good idea! I have a suggestion to test whether shore (or other) power is properly wired and grounded and polarity is correct. Buy a $10 GFI outlet tester. It plugs in to a standard 3 prong outlet and has three indicator lights on it to tell you if things are right or not. Home Depot or any such place has them. It also has a button on it which should trip a GFI when pushed (routes a little power from hot to neutral, to hot to ground) . Use mine most every day.
Back to the original generator question, I'd like to hear about the setups and performance of some of you with solar panels....

[Sea Wolf]

capneo-

Thanks for the great explanation!

A GFI tester would be a very valuable addition to the bus bar, and could be left in place to test periodically.

More cheap insurance, and you only have to buy it once, no annual premium!

Can you do this for the rest of my car, boat, and homeowners bills?

What C-Dory model interests you the most?

Welcome aboard and thanks for the post!

Joe.

[capneo]

No problem, Joe!
I love useful inexpensive stuff!
I'd like to wind up with a 22 cruiser. The 16 is too smal for mel, and the 25 is more complex (head/shower, mostly) and heavier for towing than I'd like. I like things simple, efficient, and I like camping, which matches the 22 most, probably.
As soon as I master my own finances, I'll tackle yours!!
Don't hold your breathe!!

[Lucky Day]

I want to add a simple question to this old thread. How exactly would I connect my EU2000 to the 110V shore power input. I am going to use a 3-prong orange extension cord plugged into the generator. I'll need to convert the female end of the extension cord so I can connect to the 30amp male plug on the boat. Where would I get the necessary hardware?

[mikeporterinmd]

[Lucky Day]

Mike,
Thanks for the info. David