Navigating Electrical Safety Through Marina Waters
I don’t know about where you reside, but the race is on here in Michigan! The frenzied months of April and May are spent uncovering and cleaning boats, in anticipation of considerable time spent on the water over Memorial Day weekend. But as the boat gets loaded with safety items like fire extinguishers, life jackets, and buoys, it is just as important to consider an additional safety consideration – electrical safety.
It's no secret that water and electricity don’t play nice together. Often, boats are docked in marinas that have both readily available. So, it is extremely important to make sure that shore power and onboard vessel electrical systems are working properly, and not introducing electrical safety hazards into marina waters. One safety concern that needs to be taken into consideration, that integrates both water and electricity, is electric shock drowning (ESD). ESD is the result of the passage of a typically low-level AC current through the body with sufficient force to cause skeletal muscular paralysis, rendering the victim unable to help themselves, while immersed in freshwater, eventually resulting in drowning of the victim. Considering I am a 3rd generation master electrician, and father, from the state of Michigan, which has the most freshwater coastline of any U.S. state, it is frustrating to me that I had never heard of ESD prior to joining NFPA two years ago. With a high level of ESD cases happening because of leakage current within marinas, it’s a great starting point for discussing what electrical professionals can do to help increase electrical safety.
First, a little history. The National Electrical Code® (NEC®), Article 555 Marinas, Boatyards, Floating Buildings, and Commercial and Noncommercial Docking Facilities has seen significant changes around marina ground-fault protection requirements, over the past several cycles. Section 555.3 of the 2011 NEC implemented a requirement for the main overcurrent protective device that feeds the marina to have ground-protection set to open at 100 milliamps (mA) or above. The substantiation behind accepted Proposal 19-189 included information of more than 50 deaths and over 30 injuries due to leakage current in or around marinas. This requirement stayed at 100 mA for both the 2011 and 2014 versions of the NEC. In November 2014, the Fire Protection Research Foundation (FPRF) released a report that assessed hazardous voltage and current within marinas, boatyards, and floating buildings. During the development of the 2017 NEC, Code Making Panel 19 (CMP-19) issued a First Revision (FR) to 555.3, changing the ground fault protection threshold from 100mA to 30 mA. The 30mA requirement was for both feeder and branch circuit conductors, as well as receptacles feeding shore power. The committee statement issued to substantiate the change stated: The 30 mA ground fault limit is consistent with that recommended in the Fire Protection Research Foundation report “Assessment of Hazardous Voltage/Current in Marinas, Boatyards and Floating Buildings.” During the 2020 NEC development process, section 555.3 covering ground-fault protection in marinas was relocated to 555.35 and broken down to cover both ground-fault protection of equipment (GFPE) and ground-fault circuit-interrupter (GFCI) protection. After several Public Inputs (PIs) were submitted that provided information around the viability of marinas being able to operate with an overall 30 mA threshold, CMP-19 created a FR to modify the existing requirement. The modified the ratings to 100 mA for feeder and branch circuit conductors, and 30 mA for receptacles providing shore power. The 30mA NEC requirement for shore power GFPE also aligned with the American Boat and Yacht Council (ABYC) Standard E-11 AC and DC Electrical Systems on Boats requirement of a 30 mA rated leakage current monitoring device being installed in all newly manufactured boats onboard electrical systems.
Leakage current is often attributed to boats themselves. In a NFPA video around the 2020 NEC marina electrical safety changes, Cliff Norton with Bellingham Marine Utilities, and CMP-7 member, estimates that 90 percent of marina GFPE issues can be attributed to the vessels, or boats, that are docked there. As you can imagine, marinas see boats of all shapes, sizes, and ages entering their waters. Some may be docked long term and some may be short term guests, but all are capable of introducing leakage current into the waters. That said, boats should be regularly tested for leakage current with the proper leakage current measurement device. For any marina having more than three receptacles providing shore power to boats, that is inspected based on the 2020 NEC, it is actually a requirement [555.35(B)]to have a leakage current measurement device on site and be utilized to determine leakage current from each boat that will utilize shore power.
So, as electrical professionals, what can be done to help ensure that marinas are as safe as possible for those about to embark on their summer of fun on the water? Here are a few things that can certainly help:
- Ensure that the marinas you service have proper GFPE protection, and it has been tested. As mentioned, there are different GFPE protection requirements based on what version of the NEC is being enforced by the jurisdiction in which the marina is located. It is important that GFPE protection within marinas meets, or exceeds, what is required.
- Ensure that the marinas have a leakage current monitoring device on hand and are regularly testing boats utilizing shore power. Every new boat that enters a marina can introduce potential hazards. Even those regularly docked at the marina every season can introduce hazards, especially when the boat onboard electrical systems are being serviced by unqualified persons.
- Learn more about ESD and spread the word to others. With nearly 30 years of an experience as an electrician in a state where everyone spends their summer on the water, I had no clue what ESD even was until I started at NFPA. For those who still don’t understand the importance, share this heart wrenching story with them. Nobody should be swimming in marina waters - at any time. In the blink of an eye, any fun-filled summer day could become a tragedy.