Pay heed when you see Grand Lake Sailing Club’s signs posted on our docks that say,
“No Swimming! Warning! Potential Shock Hazard”
Our docks have AC power and any dock with power has the possibility of “leaking” electricity into the water. Our club adheres to electrical safety precautions; we have ground fault circuit interrupter (GFCI) breakers on all our shore power pedestals and on all marina wiring circuits. These are inspected routinely, but it is still possible, even with our precautions, that electricity may “leak” into the water, possibly from a boat with faulty electrical equipment.
If electric current is present in fresh water and someone swims into that energized water, the result can be electric shock drowning (ESD). If the current is strong enough, the electric shock can cause muscle paralysis, which leaves the affected individual unable to swim to safety. It is particularly dangerous because it’s impossible to tell by sight if the water is energized.
A victim of ESD doesn’t always appear to struggle because they physically can’t. Their diaphragm is paralyzed, their swimming muscles are incapacitated, and they simply sink.
If a swimmer feels anything akin to electric current, such as tingling on the skin or a pulsing sensation in the water, they should swim away from anything that could be energized. They should shout to let others know, try to stay upright, tuck his or her legs up to make him or herself smaller, and swim away from anything that could be energized. Do not head to a boat or dock ladders to get out. Do not go to a dock with electric service or a boat that’s plugged into shore power. If possible, swim to shore instead.
What to do if you see someone who you suspect is getting shocked:
Do not immediately jump in to save them.
Throw them a life ring or float but do NOT pull the person towards the dock.
Turn off the shore power connection at the meter base, and/or unplug shore power cords.
Try to eliminate the source of electricity as quickly as possible.
Then call for help.
Reminder to GLSC Sailors:
- When you go for a sail, switch off AC power breakers onboard and at the shore power pedestal and unplug the power cord.
- Never use 120-volt power tools from a tender or float, or even in a way where wet conditions can create a ground through you. Using power tools near water can be lethal.
- If you must swim in the marina, unplug yours and nearby boats and turn off pedestal breakers and battery switches. This should eliminate the remote risk of a severe fault.
- Move your boat at least 150 yards from any marina before entering the water to perform maintenance or to swim.
According to the Electric Shock Drowning Prevention Association (ESDPA), between 10 and 15 milliamps, which is just 1/50 the wattage of a 60-watt light bulb, can cause drowning. The electricity that enters the water and causes ESD originates from the wiring of the dock or marina, or from boats that are connected to the marina’s power supply.
Would you think of stepping into a bathtub with a hair dryer?
Think of the boat as the hairdryer. If an electric fault occurs on a boat while it’s connected to shore power, the water surrounding the boat will become electrified. Often, the electric fault occurring aboard the boat is intermittent. For example, the fault may only occur when a light switch is turned on, or when a hot water heater, battery charger, or other electrical device cycles on.
Be safe. Do not swim around docks and boats using electricity!!
Consider the ENTIRE dock dangerous.
For more information, go to the Electric Shock Drowning Prevention Association’s website at https://www.electricshockdrowning.org .
Source: Practical Sailor, Preventing Electric Shock at the Dock, published July 15, 2019, updated July 15, 2020
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