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Electrical Safety:

Electric Shock Drowning: (ESD)

The danger of electrocution in the water near boats and marinas.



Electrical systems on boats are the major cause of boat fires, but they also cause other problems leading to serious injuries or death.  Electric Shock Drowning, is one of these. ESD unfortunately seems to kill or injure far more children than adults. The above video is by Kevin Ritz whose son Lucas was killed by ESD. Since then he has become the leading expert on this insidious problem and has helped to prevent many deaths that might otherwise have occurred. See Electric Shock Drowning Prevention Association

ESD is caused by faulty alternating current circuits leaking 120 volt electricity into the water. The source is faulty wiring on the boat or on the dock.  It occurs primarily in fresh water because of fresh water's high resistance to current flow.  It rarely happens in salt water because of its' low resistance to current flow.  It occurs most often at marinas with electrical hookups or boats with Alternating Current Systems. 

Boatbuilders have no control over the wiring on the dock. (however, the dock should be wired in accordance with NFPA 303. )  But they do have control over the wiring on their boats.  Builders must follow the USCG ( and ABYC ( Or ISO standards for electrical systems.  They also need to put information in the owners manual about Electric Shock Drowning and why it is so important that boat owners not alter the electrical system without the assistance of a certified marine electrician.

Any boat with AC systems should have:

A galvanic isolator or an isolation transformer;

An ELCI (Electrical Leakage Circuit Interrupter);

See for info on Isolation Transformers and ELCI;

All boats should be wired in accordance with ABYC standard E-11 ( for Electrical Systems on Boats.


The Owners Manual for a boat with an Alternating Current System and shore power should include:

NEVER SWIM AT A MARINA!  or at any dock with electrical power.

Do not let children swim off a boat that is hooked up to AC or has a generator running (not to mention the problem of carbon monoxide from the generator exhaust).  If you touch metal on your boat or on the dock and get a shock or even a tingling immediately shut everything off and have an electrician check it out.  You must do the same thing if you suspect the shore power hookup, or get a reverse polarity alarm from the shore tie. Also, many boats now have an ELCI circuit interrupter in the shore power connection. If it trips it is time to call the electrician.

Never cut the green wire.  In addition to electric shock drowning there is a significant shock hazard on any boat that has an AC electrical system and has a ground fault in that system. You could get a shock simply by touching the metal case of an appliance. The green wire, the third wire, also called the grounding wire is there to protect you from shock. Using household appliances (refrigerators, washers, dryers etc.) can create a shock hazard because in most of these appliances the green wire is connected to the metal case and the white neutral wire inside the appliance. This is correct for shore side installations but not for boat installations.  These connections between the green wire and the white wire should be removed and the green wire connected to the metal case of the appliance,  before installing the appliance on a boat.  A marine electrician knows this.  Always have your electrical system checked at least annually, and unless you have experience working with AC electrical systems, hire an ABYC Certified Marine Electrician to do electrical work.

In addition, cutting or disconnecting the green wire can result in current leaking into the water.  This can cause ESD,  or also stray current corrosion on your boat. See Corrosion On Boats

Low voltage Direct Current  electricity (DC under 50 volts) may not offer a shock hazard but it can start fires. A DC short circuit can dump thousands of amps in an instant and melt wires and circuit boards, and set your boat ablaze. Make sure your boat meets all US Coast Guard and ABYC standards for AC and DC systems. See the page on fires

If you do your own electrical work make sure you follow some simple safety rules

Many people who own boats do their own electrical work. If the boat has a simple system, a battery, running lights, and a few instruments, then this is probably not a problem.  But as you add instruments and electrical devices to your boat the system can get very complex. It gets even more complex if you add AC appliances and bring in power from the shore.  You may have to add another battery to run everything,  and overcurrent protection (circuit breakers or fuses) and switch panels.  If you do this it is time to get assistance from a professional.  But if you do, make sure the professional is a marine electrician or marine electrical engineer.  Electrical systems on boats are different from household AC systems!  In particular,  the way systems are grounded and how DC systems and AC systems are connected is significant.  Doing it wrong can mean your life, or at least the safety of your boat and boats around you.  The American Boat And Yacht Council, has standards for marine electrical systems, and provides courses and certification for marine electricians.  Ask the electricians if they are ABYC certified.  If they don't know what you are talking about, find someone who does.

In addition the US. Coast Guard  (in the USA) and boating authorities in many countries, have specific rules you must follow for a safe installation. See Ike's List - Electrical for sources

Also look at Electrical systems for more information. .

Keep in mind.  There are two systems on a boat where you should never try to scrimp or save a few bucks, Electrical Systems and Fuel Systems. 

© 2007 All rights reserved. revised 04/27/2021

Basic Electricity
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