Dock swimming - electrocution

Tiff Mapel

Well-Known Member
You know, having spent July 8-11 in the Wahweap slip on our boat, I wondered if Aramark/NPS was going to enforce the "no swimming" policy in the marinas. There are little signs posted, but no one sees them. There were kids jumping and sliding off boats all over the marina. Friday night was so busy, Wahweap was like a mini city.
 

Jackalope

Well-Known Member
There is a simple, but costly fix for this...
" ISOLATION TRANSFORMERS SAVE LIVES BY HELPING PREVENT ACCIDENTAL DROWNING DUE TO STRAY ELECTRICAL CURRENT! "


If every dock with power were required to use Isolation Transformers, this would be a thing of the past.
 

Red Rock Paradise

Well-Known Member
There is a simple, but costly fix for this...
" ISOLATION TRANSFORMERS SAVE LIVES BY HELPING PREVENT ACCIDENTAL DROWNING DUE TO STRAY ELECTRICAL CURRENT! "


If every dock with power were required to use Isolation Transformers, this would be a thing of the past.
If I read it right each boat would needs its own transformer to put the power source on the boat which would mean stray current wouldn't pass through the water to get back to source. If the dock had the transformer you would still be in the same situation as stray current would try to find its way back to the dock by passing through the water.
 

thebigcanoe

Well-Known Member
I spoke with the maintenance tech on the Bullfrog dock when he was troubleshooting the wiring to the panel supplying our HB.
He found the hot and neutral legs were tied together on the hot line underneath the dock. o_O
He said the wiring on the docks hasn’t been updated for at least 30 years. And they change head electrician every year and the latest one is not marine certified.
All that being said, keep yourselves out of the water around the docks to avoid the shocks.
 

Jackalope

Well-Known Member
If I read it right each boat would needs its own transformer to put the power source on the boat which would mean stray current wouldn't pass through the water to get back to source. If the dock had the transformer you would still be in the same situation as stray current would try to find its way back to the dock by passing through the water.
Isolation transformer on the dock, not grounded to shore, would work better then adding one to each boat. Each boat should install an ELCI ELCI and GFCI - Blue Sea Systems
Info: AC Ground Faults, the Boater, and ABYC—Understanding Equipment Leakage Circuit Interrupters (ELCIs) and Ground Fault Circuit Interrupters (GFCIs) to make your boat safer. - Blue Sea Systems

I installed an ELCI in 2016, on my boat.

 

Jackalope

Well-Known Member
Wouldn't GFI Breakers on all dock pedestals solve the problem?
Unfortunately No, the power need's to be isolated with a isolation transformer.
ELCI would be a good to have but not solve the problem, because your need to stop AC current from trying to go to earth ground.

You see, fresh water is not that good of an electrical conductor but, your body is MUCH much better conductor. So what happens is is if there is AC current in the water, that current is looking for the easiest path to ground. If you are swimming by, you become the conductor even at a distance. Once the shock starts, it freezes you.

Now, If you isolate the power, the AC will not be looking for earth ground, but rather the other side of the transformer that has been isolated. If there is a current leak detected that unit will detect it and the ELCI will trip.

The difference is that the power is not looking for earth ground.
 

Jackalope

Well-Known Member
Also one other note.
Yes, an isolation transformer should be used on the boat as well.
The dock is the first choice, then the boat.
 
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JimB

Member
A GFI breaker at each pedestal would detect any stray current from each boat. If the leak is occurring in the actual dock wiring then you are right.
 

JimB

Member
If you put an isolation transformer on the dock, all the boats would still be sharing the same ground, just not the same as the offshore source. Seems to me you could still have stray currents from boat to boat. If all the boats had their own isolation transformer then that problem would be solved. It would be difficult to get each boater to do that, but a major lawsuit against Aramark could be avoided by showing due diligence. I'm surprised this issue hasn't been addressed besides putting up a few "no swimming" signs with no enforcement.
 

Jackalope

Well-Known Member
A GFI breaker at each pedestal would detect any stray current from each boat. If the leak is occurring in the actual dock wiring then you are right.
It could, but you still have earth ground to deal with.

Boat to boat would not be earth ground and the ELCI would/should detect it before anyone was near the water. However, if your boat is the ground (Aluminum hull) then the ground will be contained and not try to jump to a different boat or through the water.


One other thing, if you are being shocked, you can not use the mussels in your lungs or even your heart, you freeze, and not even make a sound. <-- what I am saying here is that if you have a vest, you will still float but the shock may kill you anyway.
 

Rivergoer

Well-Known Member
Help me out here, when out on the lake running the genset, why isn’t there a problem with stray voltage seeking earth ground? I guess what I’m saying is how is the houseboat grounded to prevent stray voltage in the water? (away from the marina).

)Sorry if off topic but somewhat related)
 

JimB

Member
I believe when you are running your generator away from the dock, your ground is isolated from earth ground. Seems to me it's the same as having an isolation transformer. Jackalope? Your thoughts?
 

Jackalope

Well-Known Member
The answer is tricky, but if your boat is setup correctly and the AC is not grounded to the hull and the neutral is not tied to the ground. Then yes, you could be OK. However, Almost all appliances tie neutral to ground unless you get marine grade. Think refrigerator, freezer, TV, blenders ... you get the point. When you are generating, you are isolated from earth ground but there could be problems if things are not setup correctly.

Now to answer the question above... a few years back in Lake Powell there was a death as a result of the generator being wired wrong and grounded to the hull. I know there was a huge lawsuit over this issue, but I am not sure the outcome.

It happens, rarely but it can be worse when someone brings a portable generator with an extension cord on shore, hooked up to the boats shore power. If you are running a gen-set from the shore, hook it to the appliance and not the shore power plug. This will keep it (better) isolated. (note, this is something I used to do until I became knowledgeable.

When running the genset , sometime's my ELCI will trip, its rare but usually happens when just starting. We believe it's a 12V ground loop and not AC.
 
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