Electrocution swimming warning.

[Shortstop]

I just read an article in the latest BoatUS magazine warning of the danger of swimming in marinas that run 110v electricity to boats. They cited several instances of deaths of children recently. Often the person jumping in to save the person dies too. It talked about how some strengths kill right away while lesser strengths paralyze, causing drowning.
My club has taken a stronger position on enforcing the No Swimming rule in our association in the marina, but we still have a lot of swimmers, including me. I think I might rethink that - this article made it real clear, swimming near electricity should not be done. It went on to talk about how you can minimize risk with GFI's (Europe requires) and other ways, but thats not cheap and in addition to the clubs line, each boat needs protection.

[Heaven]

Originally Posted by Shortstop

I just read an article in the latest BoatUS magazine warning of the danger of swimming in marinas that run 110v electricity to boats. They cited several instances of deaths of children recently. Often the person jumping in to save the person dies too. It talked about how some strengths kill right away while lesser strengths paralyze, causing drowning.
My club has taken a stronger position on enforcing the No Swimming rule in our association in the marina, but we still have a lot of swimmers, including me. I think I might rethink that - this article made it real clear, swimming near electricity should not be done. It went on to talk about how you can minimize risk with GFI's (Europe requires) and other ways, but thats not cheap and in addition to the clubs line, each boat needs protection.

How is it that people can afford boats but not afford to GFI protect the electrical circuits? Boggles the mind.

[ishoot308]

Correct me if I am wrong but isn't it pretty much national code that all outlets near any water or water source and all exterior outlets be GFI protected...shouldn't the marina's electrical outlets all be protected by GFI??? Yes, I agree that boats before hooking up should also have their own GFI as a double source of protection but the main power source supplied by the marina should definitely be on a GFI.

Would anyone here run power to their dock that was not GFI protected...that would be insane and quite illegal!

Dan

[Shortstop]

Yeah - now that you mention it - I'm no electrician, but I know any electrical work near a pool/hot tub, bathroom sink, lake,...., should be GFI protected. I'm not sure if we are, but I will certainly check this weekend.

[jrc]

There are electrical codes for how boats and marinas need to be wired. Most modern boats with shore power have GFI on some of their outlets like the bathroom or cockpit.

The marina power connection to the boats usually are GFI only if it's a standard house plug, the round shore power plugs are not usually GFI. Remember GFI only protects stuff plugged into the GFI and plugs downstream from the GFI. It does not protect the marina wiring to the GFI.

So in order to protect swimmers from bad wiring in a marina, you would need a GFI on all the wires going from shore to the marina. I've never seen that done, I don't even know if it's possible.

There is no $20 GFI solution to this risk. The whole marina needs to be wired right to begin with and the wiring needs to be maintained. Maintenance is usually the issue. Stuff gets stepped on, hit by boats, beat up by ice, and corroded.

[ishoot308]

JRC;

I understand what you are saying, but I believe code would require a GFI from the main breaker box on shore that way if anything happens to the wiring going to the docks the GFI pops and you are safe. I am not an electrician so maybe someone who is can chime in.

I honestly cannot imagine any marina would ever supply power to a dock that is not GFI protected at the panel. This simply boggles the mind...

Dan

[jrc]

I'm not an electrician so I don't know all the codes. I've never seen a whole marina or whole dock GFI. Might be a good idea, might be impossible, might be be illegal.

I used to swim in the marina at Samoset all the time, usually between the dock and my moored boat. Never gave it much thought. But reading since then and remembering the wiring conditions there probably was some risk. And they didn't even have shore power for boats just lights on the docks.

Some of these big marinas with dozens or hundreds of boats, some over 30 years old, have to be even riskier.

[SIKSUKR]

This one has me scratching my head.There are stray voltages but I can't imagine a short to ground(water) with enough voltage to kill somebody that would not trip the breaker even without a gfi.Gfi's are really just a fast acting breaker.

[ishoot308]

Originally Posted by SIKSUKR

This one has me scratching my head.There are stray voltages but I can't imagine a short to ground(water) with enough voltage to kill somebody that would not trip the breaker even without a gfi.Gfi's are really just a fast acting breaker.

My guess would be improper or no grounding...

[NoBozo]

Maybe just enough Stray current to affect certain peoples heart rythm....like a Pacemaker in reverse. NB

[jetskier]

Actually it is a GFCI (ground fault circuit interrupter). There are three connections in the circuit: power, return, ground.

During normal operation all of the current flows between power and return. A GFCI measures the current on the power feed and the return. If there is an imbalance, the breaker flips. Essentially, it means that the current is going somewhere else to ultimately get to ground (potentially through you). A difference of about 6 ma will trip a GFCI...note that your normal breaker is 15 amps or 30 amps or more of current delivered across the power/return circuit.

A current of 60 ma or higher (at 120v, 60 hz) can cause ventricular fibrillation. This is measured based upon the touch point being a dry hand. If you are swimming, your body impedence is actually much lower and ventricular fibrillation can occur at a much lower current.

So, the bottom line is that everything should be GFCI protected and the GFCIs should be tested to verify that they are working correctly.

[SIKSUKR]

Actually,Jetskier is right on about how a gfci trips.A simple breaker trips by having too much current travel through it.That why I contend that having current high enough to kill going into the lake without tripping a breaker seems impossible except for a very brief moment.

[birchhaven]

I am probably way off, but I will throw this out there for someone smarter than me to finish.

When I was considering adding a irrigation system to my lawn. One contractor suggested pulling water from the lake. He said there is two ways to do it but only one right way. What he said is the wrong way is putting the pump in the lake, rather than on the land sucking it out.
He said that the pump in the lake can create an electrical field that will zap a swimmer even tho no electrical current would be going from the wires to the water, as in it is installed properly and there is no reason for the breaker to pop.
He could have been blowing smoke but he sounded like he knew what he was talking about.
Does any body else know what he was talking about? I wonder if a similar thing is happening with people swimming in a marina, since marinas tend to pack some serious amperage.

[codeman671]

Originally Posted by birchhaven

I am probably way off, but I will throw this out there for someone smarter than me to finish.

When I was considering adding a irrigation system to my lawn. One contractor suggested pulling water from the lake. He said there is two ways to do it but only one right way. What he said is the wrong way is putting the pump in the lake, rather than on the land sucking it out.
He said that the pump in the lake can create an electrical field that will zap a swimmer even tho no electrical current would be going from the wires to the water, as in it is installed properly and there is no reason for the breaker to pop.
He could have been blowing smoke but he sounded like he knew what he was talking about.
Does any body else know what he was talking about? I wonder if a similar thing is happening with people swimming in a marina, since marinas tend to pack some serious amperage.

The water pump for our house is a submersible 220v pump. There is nothing wrong with using one as long as it is set up properly. It is easier since you dont have to winterize the pump, just blow out the lines in the house at the end of the season. Submersible (below) and jet pumps (above) are the 2 options used.

Ours is within 20 feet of our swim raft. To date, nobody has been fried....

[jrc]

Birchhaven, knowing what I do about electricity, there is no way you could get enough energy from this type of electric field to hurt anybody. The frequency and power levels are way to low to couple anything.

Now a submersable pump is theoretically prone to physical damage to the motor or wire insulation that could couple power directly to the water. An onshore pump is less vulnerable.

Theres lots about electcuting swimmers on the internet. I read that salt water is safer than fresh. If a bare hot conductor is in the water, some of the current will travel through the water to ground, as it's the easiest path. Since salt water is more conductive than humans, the current stays in the water and out of your body. Since lake water is less conductive, you become the path of least resistance.

[AkwaMarina]

https://cc.readytalk.com/cc/playback...k.do?id=5h5qwc

Eaton Marine did some great webinares on this. I hope the link works, it should be free to view for ~30 days

[Bear Islander]

I am a New Hampshire licensed Master Electrician. GFCI protection is only required on NEW construction. If you have an old electrical system and you just keep fixing it and using it there is no requirement that you add GFCI protection.

As has been mentioned the only way to have full protection is to put a large GFCI on the feed from shore. This would be VERY expensive and not required by the National Electric Code. Also this GFCI would be subject to a lot of nuisance tripping. After the the power went out a few times people would be screaming to eliminate the expensive GFCI that is not required by code.

I would never run 120 volt or 240 volt power to my dock and it is not smart to swim around voltages like that. Low voltage lighting is available and is cheap, safe and easy to install. Other than low voltage the only good answer is stay away from electricity when in the water.

[camp guy]

Thanks to BI for the view from a Master Electrician.

I fully understand the concept of "grandfathering", but it always bothers me when something as potentially (no pun intended, but I'll take it!) dangerous as electricity and water are allowed to slide due to age. Wouldn't it make sense to do just the opposite - old wiring needs to be brought to Code for the very fact that it is old.

I have said this before, and I will say it again, and again, there is no short-cut around safety - none whatsoever. I've had my say.

[NoBozo]

I actually have experience with STRAY currents in the water near a dock. A few years ago we went to the Thousand Islands with our little Donzi. We stayed at a motel on the "Other" side of the river just southwest of the International Bridge. I think the name of the motel was The Torchlight. There was enough space at their dock for two boats. We were one of them.

In one week..maybe a little more..the weather was so freakin HOT, we never went out in the boat. We left it at the dock and went to the Clayton Museum by truck and spent the day there sitting under a tree. During that time at the dock..The outdrive SHED it's paint. The paint was mine...with propper prep. over factory paint. There was a little "Pump House" on the dock. Just sayin'. NB

[ishoot308]

Originally Posted by Bear Islander

I am a New Hampshire licensed Master Electrician. GFCI protection is only required on NEW construction. If you have an old electrical system and you just keep fixing it and using it there is no requirement that you add GFCI protection.

As has been mentioned the only way to have full protection is to put a large GFCI on the feed from shore. This would be VERY expensive and not required by the National Electric Code.

Bear Islander;

Thanks for your input!! I am curious however where the main expense would be and why you think it would be "VERY expensive"?? Wouldn't simply changing out the breaker in the main panel to a GFCI take care of the issue?? GFCI breakers are very inexpensive ($20.00 - $30.00) as I just rewired my entire place and had to do this for my dock electrical.

Thanks!!

Dan

[Winnisquamguy]

Originally Posted by Bear Islander

I am a New Hampshire licensed Master Electrician. GFCI protection is only required on NEW construction. If you have an old electrical system and you just keep fixing it and using it there is no requirement that you add GFCI protection.

But is that the right way to do it? If its not broke don't fix it? I thought GFCI's were pretty cheap, sounds like a no brainer to me.

[birchhaven]

Originally Posted by AkwaMarina

https://cc.readytalk.com/cc/playback...k.do?id=5h5qwc

Eaton Marine did some great webinares on this. I hope the link works, it should be free to view for ~30 days

This video explained this incredible well. I now know more than I ever wanted to know about this.

But it got my wheels turning, could a person install an underwater ground rod in the lake bottom (say 6 feet from lake bottom, in 10 feet of water under the dock), so if your boat has leakage, the ground rod will complete the circuit before a unsuspecting swimmer does?

[jrc]

Obviously thinking about a few dollars for a single outlet in a home environment is one thing, but think about a marina.

Each boat can have two 30 amp shore power outlets. So a place like MVYC has 300 boats, thats an 18,000 amp GFI. So maybe they don't have one big one but 600 small ones, a 30 amp GFI is $150 plus labor. That's $90,000 in parts alone. Even still all the feeds to the breaker panels are vulnerable.

I'd rather just not swim at the marina than trust that they will spend all this money and didn't screw something up.

[SIKSUKR]

Your house has a 3-wire system using one wire to ground to the earth under your house to carry the energy away from you and allow it to discharge into the ground protecting you from electrocution.

Your boat doesn't sit on the ground or earth--it floats, so you cannot run a ground wire to the earth under the boat.

The 12V system (2-wire) on the boat grounds back to the battery. The negative terminal on the battery is connected to a grounding cable connecting all the metal surfaces on the hull. This bonding system equalizes potential current between the fittings elliminating any potential difference in voltage between the fittings. This not only protects you from electric shock, it also helps reduce corrosion.

110V Shore Power or Generator Power is a totally separate, independent wiring system. It is a 3-wire system that is grounded back to shore, or the generator.

When Something Goes Wrong

When an uninsulated part of a 110V (hot) live wire comes in contact with an uninsulated part of a 12V wire, the uninsulated 110V then uses the 12V ground, making all the metal parts on the bottom of the boat live with 110V. Because fresh water is a poor conductor, it forms a gradient around the boat. If a person enters this gradient while swimming, the current will flow through the body causing paralysis or ventricular fibrillation and death because the the human body is a better conductor than fresh water.

A parallel we've all heard about is a car becoming electrified when live hydro wires fall and touch the metal of the car. The rubber tires insulate if from ground. When a person standing on the ground touches the vehicle, the current passes through the body to get to ground, electrocuting the person. The human body is a better conductor than rubber, air or water.

It's no different on the boat. When a person enters the gradient around the boat, the current passes through the body to get to ground and the person dies from electric shock. The only difference is that there is no burn mark on the victim in the water and the death is usually labelled as drowning.

What Causes a Fault?

Faults causing this gradient can occur from frayed, corroded or faulty wiring, poorly installed or non-marine appliances (marine and onshore residential electrical standards and safety requirements have some very important differences). It could be caused by a current leak from electrical components such as pumps, refrigerators or battery chargers or a non-approved receptacle. It could also be caused by hull movement chaffing or rats or other animals chewing wires. Using automotive-type battery chargers or running appliances on domestic 2-wire extension cords could also cause a fault. It could also be caused by reverse polarity if the wiring on the dock or the wiring in the boat or an appliance has black and white wires reversed. If a domestic appliance with two prongs is used, there is no ground and it's a 50% chance that it can get plugged in the wrong way.

You will read in Kevin Ritz's story that a random sampling of 50 boats in three freshwater marinas in the Portland area found 26% had faulty wiring. So, even if you have had your boat checked, you have to be aware of all the other boats around you as well.

Stray Current is Destructive and Dangerous

I was alarmed that such a high percentage of boats had faulty wiring; but, I spoke with local marine technicians who agreed with the finding and shared some of their stories. There are too many to print, but I can share a few with you.

One technician told me of a boat that had its prop and outdrive eaten off by electrolysis (in just three weeks) from current leaking into the water. It took him some time to find the problem, but he found that the boat owner had put a screw into a bulkhead and unknowingly screwed through a 110V wire causing it to ground to the 12V system. The 110V went straight to the 12V grounding system into the water and destroyed his props and drives. If he had jumped into the water around his boat, he would probably have died from electric shock--all because of one misplaced screw.

Another case was a woman who complained about her legs and feet tingling when she put them into the water from the platform. The marine technician pulled the Shore Cord (laying in the water between the dock receptacle and the boat) and the tingling stopped. It turns out the shore cord was old and dried and cracked and there was leakage of the 110V current directly into the water.

Apparently, marine technicians are constantly finding wires improperly joined and uninsulated--just twisted together. The movement of the boat can shift the wires and cause a fault, resulting in current leakage into the water.

For NoBozo:

One boat owner had severely corroded props and drives and when the marine technician investigated, he found that the sailboat next to him had faulty wiring and there was a gradient around the sailboat from the 110V leakage that was enough to destroy the props and drives on the boats on both sides as well as damage to his underwater gear.

[NoBozo]

Originally Posted by SIKSUKR

For NoBozo:

One boat owner had severely corroded props and drives and when the marine technician investigated, he found that the sailboat next to him had faulty wiring and there was a gradient around the sailboat from the 110V leakage that was enough to destroy the props and drives on the boats on both sides as well as damage to his underwater gear.

A very similar thing happened to me when I had my salt water sailboat in a marina. The fellow next to me had a "proper" marine shore power cord running from the floating dock to his onboard shore power recepticle to provide 120 volts AC to a recepticle in the cabin. There were no factory provisions to charge/maintain his batterys. The factory installed 120 volt wiring in the boat was NOT connected to the 12V system in the boat... SO..he brought aboard a car battery charger and plugged it in to this 120 volt recepticle, then clipped the charger output wires to his batterys, which he would activate when he left the boat unattended on occassion.

This arrangement is as best I could figure out after the fact.

Three weeks after spring launch my two prop shaft Zincs were gone. In addition to those zincs I also had a Zinc "Fish" hanging over the side and clipped to my bonding system for extra protection. I could SEE activity on the Zinc "Fish" every time I would retreive it prior to going sailing, but it took me awhile to find the source of the problem. At the end of the season my 15 inch two bladed bronze prop was "Ragged" around the edges and beyond useful.

The TIN leaches out of the bronze and leaves a spongy material that no longer has any "Life". A bronze prop in Good condition will ring like a bell when you thump it with the end of your finger. A Dead prop will not ring, it will just make a thud. Ever tap a good quality wine glass....?? It will ring.

The guy with the Guilty boat just shrugged when I showed him the dammage. NB

[SIKSUKR]

It has a great diagram to show a simple mistake made on board with the wiring.Very interesting to me and an eye opener.

http://www.highport.com/electricalHazard.php

[NoBozo]

Originally Posted by SIKSUKR

It has a great diagram to show a simple mistake made on board with the wiring.Very interesting to me and an eye opener.

http://www.highport.com/electricalHazard.php

I was an engineer before I retired. I LOVE technical stuff. No regular person is going to read that whole article. I Did.

The bottom line is: DON'T SWIM in a Marina...PERIOD NB

POP QUIZ: Is it TIN that leaches out of Bronze..OR is it TIN that leaches out of Brass. I can't remember. Maybe one of you NEW engineers can look it up for me. NB

[mas1992bc]

I'm not an electrician, so I apologize if this is a dumb question, but I have a related question. What about swimming near a circulator (like the ones used to circulate water around your dock in the winter)? Those are plugged into shore power, with the cord running directly into the water. Obviously, nobody is swimming in the winter, but would it be unsafe to swim in the water with one of those plugged in (if, for some reason, you still had it plugged into power in the spring)?

[Belmont Resident]

Originally Posted by mas1992bc

I'm not an electrician, so I apologize if this is a dumb question, but I have a related question. What about swimming near a circulator (like the ones used to circulate water around your dock in the winter)? Those are plugged into shore power, with the cord running directly into the water. Obviously, nobody is swimming in the winter, but would it be unsafe to swim in the water with one of those plugged in (if, for some reason, you still had it plugged into power in the spring)?

I think those come out long before exposed skin goes in.
But you are correct if they were not properly ground faulted then there may be a problem.
My .02, anyone who knowingly has electricity out to their dock without proper ground fault weather it is legal because it's been there since before time or not is asking for trouble. Just curious if something did happen and a loved one or family member got hurt or worse it would still have been legal but that person would still have gotten hurt because of something you could have prevented.
2 years ago I had a truck catch on fire because the block heater wasn't plugged into a ground fault outlet. Well the garage had none in it to begin with.
The cord had broken from use and shorted on the bumper catching the grill on fire while sitting right in front of my garage. I've since changed over to arch protection outlets, costly but worth it since I'm sometimes caught working out in the rain or have things plugged in during the winter.

[kjkam]

Alot of people don't know that you can get stray voltage from the ground leg, this could be caused by improper wiring in the house or even a faulty transformer. We had this issue with our boat lifts, the soltution was to electrically insulate the motor (which the frame is grounded) from the rest of the metal on the boat lift, the utility also changed the transformer to our house. which brought it down. We could only measure about 5VAC, but that was enough to give you a tingle if you were in the water and touched the boat lift that was above the water.

[Bear Islander]

Here is another thing to think about. Every now and then the lake gets real high in the spring. The docks at my marina have been underwater during those years. Under those conditions you must walk through the water to get to your boat. Therefore it is essential that ALL power to the docks be shut down when the water gets to, or above, dock height.

[Lakegeezer]

After reading all the posts, I'm a bit confused. If there is a GFI back at the breaker, and it is tested often, is there any problem with electric power at the dock or in the water? My assumption is/was that a GFI makes it all OK - and can't believe that anyone would have dockside power unprotected this way. Or, are there situations where the GFI doesn't provide the protection required?

[XJLPS]

I was taking in an ice eater one spring in water up to my neck ,when i approached the eater I notice 3-4 salmon dead next to it , I thought maybe they got hit by the prop. Boy was I wrong I grabbed that thing and got a jolt from the unit . After killing the power we brought it on shore turned it on and put a voltmeter on it it was putting out 220 volts on the frame . Turns out it was hooked up by a guy who claims to be an electrician . I wouldnt let him change a bulb in my kids easybake oven .

[kjkam]

When I was doing my research to find the issue, there are two ways to get electricity into the water. The first is through some type of faulty wiring or installation, a dead short to the water, which would be prevented by the GFI or breaker. The second is where there are stray voltages caused by inbalanced electrical grids, faulty transformers, ect, basically caused by anything before your meter. These stray voltages are not very high and are not just found in the water, but in rare cases they can be enough to cause injury or death. The electrical grid in this country is in pretty good shape, so cases are rare.

[John A. Birdsall]

While I agree that the GFI should be in place for the waterfront (docks, etc) I have some reservations about keeping the cottage up to "code" It seems that code is a constant changing item and to keep the code up seems to be an never ending item.