Avoid electric-shock drowning
Knowing where the dangers are and how to check for leaking AC electricity in the water could be
a lifesaver. Spring is the time to do it, before you put boats and people in the water
BY DAVID RIFKIN
Sadly, each year there are numerous accidents in the waters around boats and ocks where AC electrical power is in use. Last year, at least six deaths and 15
near misses (where the potential victim
escaped death) have been identified.
Electric-shock drowning (ESD)
occurs when an AC electrical current
flowing in the water passes through
the body of an individual immersed in
the water. This current causes muscular
paralysis, impairing one’s ability to swim
or stay afloat, leading to drowning.
ESD is far more likely to occur in
freshwater than saltwater. In freshwater,
the body is a better conductor of electricity than the water itself (the opposite is
true in saltwater). Be aware that many
bodies of water can become brackish or
fresh even though they were previously
saltwater, depending on such factors as
tides, wind, and rainfall.
The causes of electrical currents leaking into the water vary but are often the
result of faulty wiring and equipment on
boats or docks. These faults are sometimes created unknowingly when a boat
owner attempts to repair or upgrade a
vessel’s electrical systems. There are differences between household wiring and
boat wiring, and if you’re not 100-percent
certain of what you’re doing with shore-power repairs, hire a professional.
Don’t go there
The most important message is this:
Never swim near any dock or boat where
AC power is in use. To reduce risk to an
acceptable level, individuals (and pets)
should never enter the water within 150
feet of any electrical equipment or wir-
ing. This pretty much eliminates swim-
ming in a marina, especially off a boat;
most marinas prohibit it anyway.
In 2011, the National Electric Code
introduced new requirements for ground-fault protection in shore-power applications in marinas and boatyards. The
latest version for 2017 expands the area
for such protection to docks at private
residences. The new requirements are
not retroactive, but owners and operators
would be wise to upgrade their facilities
to improve safety around their docks.
Upgrading can be as simple as installing a ground fault circuit interrupter
(GFCI) at the dock pedestal. This device
will trip if dangerous current escapes the
dock. The new requirements also include
warning signage on all docks (including
residential ones) using electricity.
The American Boat & Yacht Council
also added a requirement for whole-boat
ground-fault protection to its standards
several years ago, and an equipment leak-
age current interrupter (ELCI) is now
installed on new boats. Owners with
older boats should consider upgrading
their shore-power systems. The upgrade
equipment is normally installed in the
boat at the power panel and can take as
little as two hours for a pro to install.
Testing for danger
While not foolproof, you can test if dangerous electrical currents are in the water
around your boat. You’ll need an AC
clamp-type meter with a minimum resolution of 100 milliamps. With the boat
connected to shore power, clamp the cord
with the AC clamp meter. Because the
meter is reading the difference between
the current running to the boat and what’s
returning in an AC circuit, the reading
should be zero. Anything above that is
the amount of current not returning and
most likely flowing into the water around
the boat. More
than 100 milliamps
of current in freshwater and 500 milliamps in saltwater
is dangerous and
should be investigated immediately.
But this test is valid
only if everything
in the boat using
AC is turned off.
What you can do
1. Never swim around boats and docks
that use electricity.
2. Post “No Swimming” signs.
3. Have a qualified marine electrician
inspect your private dock annually.
4. Install ground-fault protection on
your boat and private dock.
5. Ask your marina to install ground-fault protection, and have the electrical
system inspected and tested annually.
6. Periodically test your boat for electrical leakage into the water.
Want to learn
ESD to access
our electric-shock-drown-ing resource