The Safe-T Corner
ESD Part One.
ESD=Electric Shock Drowning. During four months of summer 2012, there were seven confirmed ESD deaths and at least that many “near misses”; in all likelihood, dozens more incidents went undetected. Seaworthy Magazine: “Every boater and every adult who swims in a freshwater lake needs to understand how it happens, how to stop it from happening, and what to do – and not do – if they ever have to help an ESD victim.” DO YOU?
ESD occurs in fresh water where minute amounts of alternating current (AC) are present. In layman’s terms, less than a third of the electricity used to light a 40-watt light bulb passing directly though the heart is almost always fatal. So, how does electricity get into the water in the first place? In a properly functioning electrical system, all of the 120-volt AC current that goes into the boat through the shore power cord returns to its source – the transformer ashore or the dock where it originated. For any of the current to wind up in the water, three things have to occur:
1. Electrical Fault. Somewhere current is escaping from the system and trying to find another path back to its source ashore.
2. AC Safety Ground Fault. The AC grounding system must be compromised so that stray current cannot easily return to ground through the ground safety wire. The stray current has only way back: through the water.
3. No Ground Fault Protection. Any system without a Ground Fault Circuit Interrupter (GFCI) will force the electricity to flow into the water.
If all these conditions exist, then some or all of your boat’s underwater metals will be energized, and electricity will radiate out from these into the water. In fresh water, 120-volt AC will set up a dangerous voltage gradient that will pass through any swimmer who bridges it. The swimmer grabs the metal ladder and is electrocuted.
To protect against ESD accidents, the American Boat and Yacht Council (ABYC) adopted standards in 2010 that require an Equipment Leakage Circuit Interrupter (ELCI) be installed on new boats. However, not all manufacturers follow the ABYC standards, which are voluntary, and there is no requirement to retrofit ELCIs on older boats. There is also no standard that requires the installation of GFCIs at private marinas and docks. Tennessee’s proposed marina safety legislation will not apply to private marinas and boat docks and, if passed, will take effect in 2015.
NOTE: Next month’s article will address what to do and not do when helping an ESD victim.
DO YOU KNOW IF YOUR BOAT IS LEAKING CURRENT?
If in doubt, check it out! If you want your private dock inspected by a licensed master electrician, contact me and I’ll coordinate for a TCC member group rate. Thank you & B-SAFE.
Sources: Seaworthy magazine (Oct 2012, July 2013), News Sentinel newspaper
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