Electric Shock Drowning (ESD) occurs when a person in fresh water encounters stray AC current being leaked from a boat or other shore side power source. The current is attempting to return to its source and finds a human body to be a better conductor than the fresh water it is immersed in. This causes skeletal muscular paralysis and renders the victim unable to help him/herself and subsequently drowning. ESD only happens in fresh water. Sea water is 300 times more conductive than fresh water and human bodies are saline–about the same conductivity as sea water. In fresh water a body is like a floating island of good conductivity. It only takes a small voltage gradient in the water (as little as 2 volts per foot) to cause cardiac and respiratory paralysis. Most victims are young, because young people are more likely to be frolicking in the water. And often the first victim is followed by a second, who jumps in the water to help someone who appears to be drowning.
According to the American Boat & Yacht Council Technical Standards Specialist, Matt Wienold, there is typically no evidence that a problem exists prior to entering the water, or even after an incident has occurred. If enough current is in the water, electrocution occurs, yet no burn marks are left behind as seen in other electrocutions. Oftentimes the current in such incidents is intermittent making the determination of cause even more difficult. Marinas that are improperly wired, malfunctioning onboard appliances and (most of all) AC units on boats are major culprits in ESD.
The reported number of ESD incidents has gone up at an alarming rate over the past few years. If you have a case involving ESD, CED Investigative Technologies has mechanical and electrical engineers that can help. To speak with one of our representatives call us at 800-780-4221.