electric leakage - marina boat dock

Status
Not open for further replies.
We just had a sad Incident where two girls drowned at a local lake and it was determined that it was due to electrical leakage from faulty wiring on a boat dock. I have several friends on that lake and some of them have been asking me the best way to test/prevent this. my main suggestions were

the power is fed from a Gfci breaker at the source vesus using gfci receptacles at the doc.
test the gfci regularly especially during the summer months
make sure all the wiring is uf and rated for outdoor or wet environments

what is the best way to test for problems ,
what other advice would you give a home owner with a boat Dock.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The best advice is that no one is in the water within a 100' from the dock. One of the issues is an elevated neutral to ground voltage that also acts to elevate the voltage of the EGC and can cause problems.
 

mgookin

Senior Member
Location
Fort Myers, FL
We just had a sad Incident where two girls drowned at a local lake and it was determined that it was due to electrical leakage from faulty wiring on a boat dock. I have several friends on that lake and some of them have been asking me the best way to test/prevent this. my main suggestions were

the power is fed from a Gfci breaker at the source vesus using gfci receptacles at the doc.
test the gfci regularly especially during the summer months
make sure all the wiring is uf and rated for outdoor or wet environments

what is the best way to test for problems ,
what other advice would you give a home owner with a boat Dock.

I'm very sorry to hear about the loss of life of the kids who were just being kids.

I suggest an armored conduit system for your wiring and periodic inspections of it. Since you're saying lake I'm assuming you have no salt (although some lakes do have salt). My experience is with Florida sun, tides, storms and salt water. Nothing survives the installation forever but the more you put into it, the longer you can get out of it.

I like your GFCI before it leaves the shore. While working in a building department I convinced every applicant for a marine electrical permit to do that long before it was code. We would have a few kids die one year, then go a few years with no problems, then another wave of kids getting killed. In every case it was the branch circuit under the dock which killed them; it was never anything after a receptacle or load. The better you can armor that installation to protect it from the elements which cause failure, the better chance you have of protecting those in the water. It needs to be inspected periodically.
 

Fitzdrew516

Senior Member
Location
Cincinnati, OH
I'm very sorry to hear about the loss of life of the kids who were just being kids.

I suggest an armored conduit system for your wiring and periodic inspections of it. Since you're saying lake I'm assuming you have no salt (although some lakes do have salt). My experience is with Florida sun, tides, storms and salt water. Nothing survives the installation forever but the more you put into it, the longer you can get out of it.

I like your GFCI before it leaves the shore. While working in a building department I convinced every applicant for a marine electrical permit to do that long before it was code. We would have a few kids die one year, then go a few years with no problems, then another wave of kids getting killed. In every case it was the branch circuit under the dock which killed them; it was never anything after a receptacle or load. The better you can armor that installation to protect it from the elements which cause failure, the better chance you have of protecting those in the water. It needs to be inspected periodically.

It's gotta be freshwater. Electrical shock drowning doesn't occur in saltwater due to the conductivity of the saltwater.

I have heard of people installing isolation transformers, but the more common application is GFCI.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Short of operating an ungrounded system on each boat, I do not see the potential benefit of an isolation transformer (unless there is a very high neutral/EGC offset from water ground which should be corrected seperately.)
 

fmtjfw

Senior Member
GFCI not a life safety protection in Marinia, Just indicate deterioration.

GFCI not a life safety protection in Marinia, Just indicate deterioration.

GFCIs on marinas (for boats) need not be 6ma, they are allowed to be up to 100ma. 100ma can kill you, but has fewer nuisance trips.
General purpose receptacles are still at 6ma. The "service" (main ocpd) must have 100ma or below. Some places try for 30ma on feeders or branches.

The main thing is to stay out of the water. Neither swim nor fall in.
 

luckylerado

Senior Member
We just had a sad Incident where two girls drowned at a local lake and it was determined that it was due to electrical leakage from faulty wiring on a boat dock. I have several friends on that lake and some of them have been asking me the best way to test/prevent this. my main suggestions were

the power is fed from a Gfci breaker at the source vesus using gfci receptacles at the doc.
test the gfci regularly especially during the summer months
make sure all the wiring is uf and rated for outdoor or wet environments

what is the best way to test for problems ,
what other advice would you give a home owner with a boat Dock.

Here are the requirements that Lake of the Ozarks has adopted. We have had several similar incidents.
 

Fitzdrew516

Senior Member
Location
Cincinnati, OH
Short of operating an ungrounded system on each boat, I do not see the potential benefit of an isolation transformer (unless there is a very high neutral/EGC offset from water ground which should be corrected seperately.)

http://www.acms-usa.com/index_files/boating_safety_issues.html

"To avoid contributing to this problem of electric shock drowning, install an isolated winding transformer in your boat between your shore power disconnect breaker and the power distribution wires. This will electrically isolate the normally current carrying AC system wires but not the AC ground wire from the normally current carrying wires of the shore power. The transformer winding transfers the power magnetically with no actual connection from the shore power to the boat’s branch circuits. There is no water path if there is a ground fault in the electrical equipment on the boat."

I'm trying to wrap my mind around this, but it seems legit, no?
 

Ingenieur

Senior Member
Location
Earth
gfci all dock circuits
may increase nuisance tripping but that is the price you pay

we hadvan issue where people got shocked
all dock ckts had gfci
the main feeder did not, from shore to dock on messanger
it abraded and fell in the water
we put gfci on the feeders after that
 

fmtjfw

Senior Member
NEC 555

NEC 555

Article 555 requires a GF rated 100ma or less on the main. Defence in depth is best. Put individual GFs on each shore power receptacle, hopefully at 6ma. worst case 30ma.
All non-shore power receptacles to be at 6ma, just like all other locations.

Although not in NEC, require inspections yearly or every two years per NFPA 303 and/or State law, as is WV.

WV requires, by law, that only Journeyman and Masters do wiring (no apprentices).
WV requires that electrical inspectors for marinas be specially trained. I taught part of the classes for the Fire Marshall as part of the program.

There have been problems with boat owners doing their own wiring, including miswiring cable to connect a hot wire to safety ground.

We've gotten lots of pushback from marina owners and users. (money ...)
 

mgookin

Senior Member
Location
Fort Myers, FL
It's gotta be freshwater. Electrical shock drowning doesn't occur in saltwater due to the conductivity of the saltwater.

I have heard of people installing isolation transformers, but the more common application is GFCI.

That's not quite correct. There have been plenty of people die from electrocution in salt water. I understand what you're saying about deltaV in salt water vs freshwater, and that's correct, but when someone's exposed to line voltage in the water and then touches something bonded they complete the circuit and often don't survive, especially if it's the branch circuit ahead of the GFCI receptacle which doesn't even have anything plugged into it anyway. Under a dock is some of the nastiest wiring there is because it does not last long under the conditions and nobody ever sees it to know it's in bad repair. The pilings are on 10' centers and often people just lay conduit from cross brace to cross brace on 10' centers. I'm not saying it's right, I'm just saying that's what happens. On very high tides (storm surge) the wiring is submerged and getting beat around by wave action and floating debris. The conduit fails and the failed conduit exposes and degrades the wire insulation.

Because the voltage gradient is greater in freshwater does not mean you can't die in saltwater.

Installing an isolation transformer on a boat and installing GFCI on land to protect the entire circuit are mitigating two different perils.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
I would also check any boats that may use shore lines to connect to their boats. You probably won't see very much of that on small lakes but boats on larger lakes and salt water marinas use them. Many boat owners like to make up their own shore lines and often mis-wire them. Lord knows how the wiring inside the boat was installed and connecting to a shore line may prove dangerous. One of the guys at a supply house that I buy from had an incident where the railing on a boat became energized. I don't believe there was any specific shock hazard at the time but the shore line was removed and the plug end cut off.
 

Fitzdrew516

Senior Member
Location
Cincinnati, OH
That's not quite correct. There have been plenty of people die from electrocution in salt water. I understand what you're saying about deltaV in salt water vs freshwater, and that's correct, but when someone's exposed to line voltage in the water and then touches something bonded they complete the circuit and often don't survive, especially if it's the branch circuit ahead of the GFCI receptacle which doesn't even have anything plugged into it anyway. Under a dock is some of the nastiest wiring there is because it does not last long under the conditions and nobody ever sees it to know it's in bad repair. The pilings are on 10' centers and often people just lay conduit from cross brace to cross brace on 10' centers. I'm not saying it's right, I'm just saying that's what happens. On very high tides (storm surge) the wiring is submerged and getting beat around by wave action and floating debris. The conduit fails and the failed conduit exposes and degrades the wire insulation.

Because the voltage gradient is greater in freshwater does not mean you can't die in saltwater.

Installing an isolation transformer on a boat and installing GFCI on land to protect the entire circuit are mitigating two different perils.

Interesting... Are the deaths you're referring to from electrocution or from drowning? I was specifically talking about ESD, but I guess in theory the math still makes sense with the right variables regardless.
 

oldsparky52

Senior Member
I would like to read an article that reported drowning from swimming in a salt water marina, if someone has a link, please share.

As far as the NEC, there is an exception to the 100ma requirement on the main (which I think is being removed in the next edition).

More and more I'm seeing drawings showing 100ma GFP on the main, then 30ma GFP on the shore power receptacles for boats. Each receptacle is protected separately (20A receptacles have the 5ma protection).

The one thing that all of this protection does not address is that a waterway can be a parallel path for the PoCo's multi-grounded distribution system and through grounding and a deteriorating neutral, you could have current leakage into the water not coming through any of the GFP or GFCI protection.
 

mgookin

Senior Member
Location
Fort Myers, FL
I don't know specifically about "saltwater marinas" and I can't say I've ever seen anyone swim in a saltwater marina other than a diver performing professional services. But in saltwater bodies of water, many.

[h=2]2 Teens Electrocuted In Canal[/h]
May 10, 2003
NORTH FORT MYERS -- Two teenage boys died when one touched an electrified boat lift while retrieving a football from a canal and the other touched it while trying to save him, officials said. Alex Kopinetz, 16, and Douglas Brandenburg, 15, were jumping on a trampoline in a neighbor's yard when Brandenburg spotted the ball and jumped in after it, Lee County sheriff's officials said. He was electrocuted when he grabbed the boat lift, which was attached to a dock. Kopinetz summoned nearby adults and jumped into the water, but as he pulled his friend to shore, he also touched the lift and was electrocuted.

Don't confuse "canal" with "freshwater". Our canals have sharks, porpoises, blue crabs and grouper in them.

In a NFPA report they report the death as "unconfirmed ventricular fibrillation". The kids got zapped by a boat lift in salt water. They are dead.

There have been several others in my 30+ years in Florida. That's what I'm able to find at the moment.
 

oldsparky52

Senior Member
I don't know specifically about "saltwater marinas" and I can't say I've ever seen anyone swim in a saltwater marina other than a diver performing professional services. But in saltwater bodies of water, many.

2 Teens Electrocuted In Canal


May 10, 2003
NORTH FORT MYERS -- Two teenage boys died when one touched an electrified boat lift while retrieving a football from a canal and the other touched it while trying to save him, officials said. Alex Kopinetz, 16, and Douglas Brandenburg, 15, were jumping on a trampoline in a neighbor's yard when Brandenburg spotted the ball and jumped in after it, Lee County sheriff's officials said. He was electrocuted when he grabbed the boat lift, which was attached to a dock. Kopinetz summoned nearby adults and jumped into the water, but as he pulled his friend to shore, he also touched the lift and was electrocuted.

Don't confuse "canal" with "freshwater". Our canals have sharks, porpoises, blue crabs and grouper in them.

In a NFPA report they report the death as "unconfirmed ventricular fibrillation". The kids got zapped by a boat lift in salt water. They are dead.

There have been several others in my 30+ years in Florida. That's what I'm able to find at the moment.

Did the boat lift have GFCI protection (like it should have)?

I've seen the service neutral/ground be at an elevated voltage from the waterway. When the mains were shut off, the voltage was still there, lift the incoming service neutral from the meter bus and it was gone. If that condition existed, having GFCI protection would not prevent the grounded boat lift from shocking those 2 boys. Was there an investigation to determine what the cause of the ESD was?

Edit: Since I observed that condition, I've driven 20' of ground rod near the waterway and tied it back to the service neutral for all jobs I work on. The PoCo does not consider this there problem (which I can't understand how it's not their problem).
 

Fitzdrew516

Senior Member
Location
Cincinnati, OH
I don't know specifically about "saltwater marinas" and I can't say I've ever seen anyone swim in a saltwater marina other than a diver performing professional services. But in saltwater bodies of water, many.

2 Teens Electrocuted In Canal


May 10, 2003
NORTH FORT MYERS -- Two teenage boys died when one touched an electrified boat lift while retrieving a football from a canal and the other touched it while trying to save him, officials said. Alex Kopinetz, 16, and Douglas Brandenburg, 15, were jumping on a trampoline in a neighbor's yard when Brandenburg spotted the ball and jumped in after it, Lee County sheriff's officials said. He was electrocuted when he grabbed the boat lift, which was attached to a dock. Kopinetz summoned nearby adults and jumped into the water, but as he pulled his friend to shore, he also touched the lift and was electrocuted.

Don't confuse "canal" with "freshwater". Our canals have sharks, porpoises, blue crabs and grouper in them.

In a NFPA report they report the death as "unconfirmed ventricular fibrillation". The kids got zapped by a boat lift in salt water. They are dead.

There have been several others in my 30+ years in Florida. That's what I'm able to find at the moment.

Got ya. So this is not a case of ESD, but it makes sense. It was direct connection to the faulty equipment, not a voltage gradient through the water that caused it.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If the neutral that is energizing metal (via an unintentional connection) is downstream of a GFCI receptacle the GFCI will activate and open both hot and neutral. A GFCI breaker will activate but not open the neutral.
If the problem is that the EGC to service neutral bond is doing the energizing, then the normal POCO reaction to "fix" it would be isolating the service neutral from the MGN, I believe.
 
Status
Not open for further replies.
Top