Another swimming season is upon us, and so I must dive again in to a discussion of marina safety. As electrical professionals, we are in a position to help make marinas a safe place to work and play. Marinas can be quite a dangerous place when it comes to electrical hazards. Let's break the ice with some thought-stimulating information that you can build on during your next marina project.
Marinas in both fresh water and salt water can present challenging locations for the electrical distribution system. The distribution system has to to weather moisture and many other elements that act to deteriorate the electrical system over time. In addition to your standard electrical system components, these locations present possible fueling stations that present different challenges and hazards unto themselves. Much of this equipment is placed on a structure that rises and sways with the waves. This is a mix that can spell disaster for an electrical systems that is not maintained or designed correctly.
This potential for disaster is all too real. When a person succumbs to electricity while swimming, it is referred to as Electrical Shock Drowning (ESD). These issues are not contained to just large marinas; small, private marinas are probably more likely to have issues than the larger facilities.
Fresh Water vs. Salt Water
Water has a resistance usually referred to as "conductivity," which is measured by applying a voltage between two electrodes and measuring the voltage drop between the probes. The drop in voltage is used to calculate the resistance. The resistance is then converted to conductivity. Conductivity of water is quite complex and dependent upon what is in the water you are addressing. The more impurities you put in water, the more conductive it becomes. Saltwater offers a good conductive solution. When the resistance of a fluid around an object is less than the resistance of the object itself, current will take the path of least resistance, which is not through the object. When a human body is in fresh water that is energized, the fresh water has a high resistance due to significantly less impurities present. The human body offers a lower resistance, so electrocution is likely. This does not mean that there is no electrical hazard for salt water applications.
Hazards exist in any location where water and electricity are in close proximity to each other, from a pond on a golf course that may have employed pumps for fountain-like attractions to the private boat dock.
Codes and Standards
There are two key documents, from an electrical perspective, that command your attention when addressing marinas and boatyards: NFPA 70, the National Electrical Code, and NFPA 303, "Fire Protection Standard for Marinas and Boatyards." The American Boat and Yacht Council (ABYC) is another organization that offers safety standards focused primarily if not entirely on the boat.
When it comes to the National Electrical Code, chapters 1-4 apply generally and chapters 5, 6, and 7 apply to special occupancies supplementing chapters 1 through 4. Chapter 5 is where we find Article 555 for "Marinas and Boatyards," which was first introduced in NEC 1968 as "Boat Harbor Wiring" and consisted of Sections 555-1 through 555-6, taking up just about a half of a page. This Article has seen attention since then and NEC 2017 didn't disappoint. It was during the 2011 code cycle that Section 555.3, "Ground-Fault Protection," was added. NEC 2017 modified this section and more.
This first change is found in Section 555.1, titled "Scope." NEC 2017 added language that expands the requirements found inside Article 555 to "one-family dwellings, two-family dwellings, and multifamily dwellings." This is a welcomed expansion from a safety perspective. A good friend of mine told me one time that an electron doesn't know it's flowing through one structure over another, let alone who owns that structure.
The second change that NEC 2017 made can be found in Section 555.3, titled "Ground-Fault Protection." This section now requires ground-fault protection not exceeding 30mA, instead of the previous ceiling threshold of 100mA. Based on research that was conducted by the NFPA Research Foundation, the threshold was reduced. In addition, the provision in the previous language that permitted the feeders and branches to be equipped with ground-fault protection instead of the main was removed. The language now reads such that all protective devices that supply the marina, boatyards, and commercial and noncommercial docking facilities must have this ground-fault protection not exceeding 30mA.
Finally, the third change that I will relay to you is found in a new section, 555.24, titled "Signage." This new requirement tells us we must provide a sign that reads as follows:
WARNING - POTENTIAL SHOCK
HAZARD - ELECTRICAL CURRENTS MAY BE PRESENT IN THE WATER.
This sign must be visible from all approaches to the marina or boatyard facility.
Marinas unfortunately take lives every summer. We can make a difference not only by creating new marinas with the latest technologies that save lives but also maintaining and updating existing marinas as they age.
Together, we can make a difference.
As always, keep safety at the top of your list and ensure you and those around you live to see another day.
Thomas Domitrovich, P.E. is VP of Technical Sales for Eaton's Bussmann business within the Circuit Protection Division of Eaton Corporation. Thomas is based out of St. Louis, MO and has more than 25 years of experience as an Electrical Engineer. He is LEED Accredited Professional and a licensed Professional Engineer in the state of Pennsylvania. Thomas is active in various trade organizations including the Independent Electrical Contractors (IEC), International Association of Electrical Inspectors (IAEI), Institute of Electrical and Electronic Engineers (IEEE), National Electrical Manufacturer's Association (NEMA) and the National Fire Protection Association (NFPA). Thomas is Principle member on Code Making Panel 2 for the National Electrical Code (NFPA 70) and an Alternate member on NFPA 73 for electrical inspections of existing dwelling units both representing NEMA.
Boat Owners Association of the United States, Electric Shock Drowning Resource Center - http:///www.boatus.com/seaworthy/ESD.asp
Energy Education Council, "Lucas' Story" - http://www.energyedcouncil.org/TLC_2014.html
Electrical Safety Foundation International, Boat and Marina Safety - http://www.esfi.org/index.cfm/page/Boating-and-Marina-Safety/pid/13101
American Boat & Yacht Council Safety, Electric Shock Drowning - http://www.abycinc.org
Electrical Construction & Maintenance, "The Case of the Hot Marina" - http://ecmweb.com/content/case-hot-marina
National Fire Protection Association, NFPA 70 "National Electrical Code" - www.nfpa.org/70
National Fire Protection Association, NFPA 303, "Fire Protection Standard for Marinas and Boatyards" - www.nfpa.org/303