Electric Shock Drowning | Boat, Dock, Pool and Spa Electrical Hazards
Summer is the time of year when people go swimming. The waters are cool, calming, and full of diverse marine life.
Unfortunately, the fun can turn fatal.
There may be an invisible danger lurking underneath. Known as the “silent killer,” electric shock drownings (ESD) occur when electric current in the water incapacitates the swimmer long enough to cause drowning.
What is electric shock drowning?
It’s a danger that you can’t see, and you can’t smell. Usually by the time you feel it, the current can paralyze the body’s skeletal muscles, inhibiting the ability to swim or move one’s limbs (i.e. electrically induced cramp). The outcome in many cases is the drowning death of an otherwise healthy individual.
ESD can occur in swimming pools, spas, lakes, marinas, and other fresh water environments.
One minute, you are splashing and having fun, the next minute, you could be dead. The danger is real. Click here for a list of Electric Shock Drowning Incidents.
While there are many dangers associated with swimming, electrical hazards are often overlooked. Don’t underestimate the danger of electrified water.
Learn how to keep your family safe and avoid electric shock drownings and electrocutions!
Electrified Water and the Human Body
When there is faulty wiring and damaged electrical equipment near boats, docks, marinas, swimming pools, and spas, there is a chance that electricity can leak into the water supply. The effect of coming into contact with electrified water ranges from mild tingling to severe burns, cardiac arrest and death.
While it is hard to predict the exact effects of any given amperage, the table below demonstrates the probable effects on the human body during an electric shock of one second.
Probable Effect on Human Body
Perception level. Slight tingling sensation. Still dangerous under certain
Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary
reactions to shocks in this range may lead to injuries.
6mA – 16mA
Painful shock, begin to lose muscular control. Commonly referred to as the freezing current or “let-go”
17mA – 99mA
Extreme pain, respiratory arrest, severe muscular
contractions. Individual cannot let go. Death is possible.
100mA – 2000mA
Ventricular fibrillation (uneven, uncoordinated pumping of the heart.) Muscular contraction and
nerve damage begins to occur. Death is likely.
Cardiac arrest, internal organ damage, and severe burns. Death is probable.
NIOSH . Worker Deaths by Electrocution; A Summary of NIOSH Surveillance and Investigative Findings. Ohio: US Health and Human Services.
Greenwald EK . Electrical Hazards and Accidents – Their Cause and Prevention. New York: Van Nostrand Reinhold.
Source: Occupational Safety and Health Administration (OSHA)
How to Prevent Electric Shock Drowning for Swimmers
Never swim in a marina, dock, or boatyard!
Do not swim during thunderstorms.
Look for “Potential Shock Hazard” signs.
Keep all electrical devices and cords at least 10 feet away from pools, spas, and docks. Use battery-operated devices if possible.
Only hire qualified electricians for electrical work.
Test ground fault circuit interrupters (GFCIs) every month to ensure they are in good working order. Learn how to test GFCIs.
All outdoor outlets should have water-proof covers.
Swap out metal ladders and rails with plastic or fiberglass ones.
Make sure everyone knows where your electrical shut-offs are located. In the event of electrified water, you will want to shut off power as soon as possible.
If you notice any faulty wiring or flickering lights around pools or spas, get out of the water (without touching metal), turn off power at the breaker box, and call a qualified electrician.
Educate your family, friends, and neighbors.
How to Prevent Electric Shock Drowning for Pool Owners
Always hire a certified electrician when doing any electrical work.
Schedule annual electrical safety inspection every year. We recommend signing up for a maintenance plan.
Everyone in your household should know how to turn off power at the electrical panel in the case of an emergency.
Never install a swimming pool, hot tub, or spa underneath power lines. Contact a qualified electrician and/or your utility company to ensure power lines are a safe distance away from your outdoor water sources.
How to Prevent ESD (for Boat Owners)
Don’t let anyone swim in a marina or near a dock. Avoid entering the water when using your boat. Both docks and boats can release electricity into the water, potentially causing electrocution and electric shock drownings.
Make sure there are no power lines overhead. Always dock your boat at least 10 feet away from the boat.
At least once a year, schedule a professional electrical safety inspection for your boat and dock. Check license numbers and make sure they follow all local and state safety codes and standards.
Test GFCIs at least once a month for proper operation. All of your outdoor and boat outlets should have GFCI protection.
Consider installing Equipment Leakage Circuit Interrupters (ELCI) on your boat(s).
If you are using an extension cord, make sure it is rated for outdoor use and has been tested by an independent testing laboratory, such as Underwriters Laboratory (UL).
Never use damaged electrical equipment or frayed wires.
If there are any doubts about your boat, dock, outdoor lighting, or swimming pool equipment, turn off power at the electrical panel and leave the power off until a qualified electrician has had a chance to check it out.
Never stand or swim in water while turning on or off electrical devices.
If you notice any electrical problems or tingling sensations, notify the property owner immediately.
To be on the safe side, shut down power to the boat or dock whenever there are swimmers around.