Electric shock drownings (ESDs) continue to occur across the country. As members of the electrical industry, we must be educated on this topic and understand what we can do to help prevent ESDs from happening.
Most people know electricity and water don’t mix. However, there are hidden dangers that even electricians don’t notice. As a society, we are increasingly building around bodies of water. Almost always, there is an electrical installation nearby to serve pool lighting, dock outlets, boat lifts, boat shore power, etc. ESD occurs when a human or animal comes in contact with voltage and current in the water. Let’s discuss the human body and how voltage and current can affect it.
Voltage is the differential potential between two points in an electrical system. Voltage is just a reference value between point A and point B. This can be very low or very high, depending on the system in reference. Amperage is the current flow between point A and point B. Research shows it takes just 9mA to start muscle contractions in the human body.
Most people think an electric shock death occurs when a person’s heart stops, after it becomes a path for electrical current. Although this can be true on dry land, exposure to electricity while in water is a different situation. Water with voltages at a very low value and very low current flow (mA) can cause muscles in the body to contract. The human skin is in direct contact with water, and the arms and legs are directly exposed with very little electrical resistance. Even an Olympic swimmer will drown if the arms and leg muscles contract and become disabled.
ESDs happen more often in bodies of fresh water than salt water. Salt water conducts electricity better and current tends to flow around the swimmer. But in fresh water or inlet brackish water, the risk is greater. In these situations, current flows through the body since the body has a lower resistance than the water.
Fish and other aquatic wildlife aren’t as prone to electric shock due to their skin and scales and their high-resistance level. So don’t expect to see a big fish kill if voltage is present in the water.
Some of you might think, “The breaker or GFCI will trip if a problem arises,” but that isn’t always the case. I think of boats around docks and marinas as hair dryers plugged in and bobbing up and down on the water. That’s a scary thought. Some newer boats have an Electric Leakage Circuit Interrupter device, but most boats don’t have one since they’ve only been implemented since 2011. And the problem isn’t isolated to docks or boats. There have been instances where current was flowing from one electric utility transformer at one home to another through a lake cove, and that circuit was never on a GFCI.
ESD can also occur in swimming pools. There are no set standards on pool safety inspections when it comes to electrical safety, especially on residential property. Rarely is the bonding and grounding system for a pool inspected, and many homeowners do their own electrical work when replacing pool pumps and lighting.
What can we do as electric service and repair electricians to help combat ESDs?
• Educate yourself and your team on the basics of ESD.
• Ensure all GFCIs are operating properly and installed in required areas.
• Check all bonding and grounding connections for signs of corrosion.
• Test for voltage in the water by using a voltmeter or voltage measuring device for water.
• Use an amp probe for measuring possible leaking current on boating shore cords.
It’s our duty to keep customers and their guests safe. ESD events are happening too often, and I believe many such deaths are misclassified as accidental drownings. Let’s do our best to prevent these tragedies and ensure the electrical devices and systems near bodies of water are safe.
