During a webinar yesterday, electric-shock drowning expert Ed Lethert warned of the dangers currently taking place in marinas around the country where docks are below the water because of flooding. Even if the pedestals or plug-in locations are above water, the lines that feed them are often below the water’s surface, which could lead to stray current in the water.
“We encourage the marinas [with power lines under water] to shut off the power regardless of inconvenience,” he said, explaining that stray current as little as 10 milliamps, which is 2 percent of the current flowing through a 60-watt bulb, is enough to cause muscular paralysis. Additional stronger current can cause respiratory paralysis and cardiac issues as well.
The webinar was hosted by the Association of Marina Industries and was one of a five-part Electrical Webinar series. AMI has also produced webinars on marina/boatyard management, safety, and a three part series on hurricane preparedness in partnership with BoatUS.
Electric shock drowning happens when a person swims in an area where electrical current has leaked into fresh water. It doesn’t happen in saltwater because the salt is a conductor and basically dissipates the current. There is no warning or indicator that there is electrical current running through the water. The problem is exacerbated because more people jump into the water to help. There have been many cases of multiple fatalities in the same incident and it extends beyond people. Pets have also succumbed.
Lethert has been involved with trying to raise awareness of ESD since 2007 and has made many presentations on the topic through the years. He insists that ground fault protection must be used in more marine applications and said that marinas and boatyards are improving their efforts to meet standards of the National Electrical Code, which has required GFCI protection for outdoor installations since 1971.
One of his biggest current concerns is the increased use of boat lifts that are often wired by their owners. “You see everything from top of the line installations to wiring that chills the spine and curdles the blood,” he said. A good alternative is a battery powered lift with solar charging.
When pulling into a marina or plugging in for the first time in a season, Lethert said there are things to look for and do before plugging in. First, visually inspect other plugs on the docks. If you see burn marks, homemade connectors or anything that looks scary don’t plug in. Tell someone from the marina.
Next, an appropriately installed and wired pedestal will have a test button on it. Before plugging in, press the test button and it should trip. The breaker should also be turned off before you plug in and before you disconnect. Once the plug is properly connected or disconnected, then turn the power back on.
On a boat, check that there is a green AC ground wire connected to the DC negative. “A short wire between the AC ground bus and the DC ground bus is critical to containing current,” Lethert said. He added that people sometimes remove the wire to decrease the chances for corrosion, but doing so creates a grounding fault and when that happens, it sends stray current in the water.
Transient boats create a tricky situation because if one shows up at a marina with an unknown problem, it can still affect correctly wired boats.
Lethert said that older houseboats are prime suspects for bad or faulty wiring and that water heaters are frequent culprits for current leakage. Additionally, marina electrical power systems need to be inspected more often.
As of March 01, 2018, most states are using the 2017 NEC distribution code that requires ground fault on all breakers in a marina. The breakers trip at 30 mA and on the 2020 code, the next update, will allow 100 mA on the feeder and 30 mA at the pedestal.
For now, the Electric Shock Drowning Prevention Association continues to promote education, awareness and mitigation. “We work with marinas trying to reduce the hazard for those in the water unintentionally, the uninformed, the misinformed, the disbelieving, people who are careless about their well-being and trespassers,” said Lethert.
More marinas need to prohibit swimming near boats that are plugged in or other electrical power sources and more need to post signs warning of the danger.
They should also have signs posted for how to shut off the power to a dock and have a main power switch that can be turned off.