Change Summary

• The ground-fault protection required for overcurrent protective devices for marinas, boatyards, and commercial and noncommercial docking facilities cannot exceed 30 mA (rather than 100 mA).

Expert Analysis

A new 555.3 was added to Article 555 for the 2011 NEC calling for “ground-fault protection” of a maximum 100 milliamperes (mA) capacity on the main overcurrent protective device serving a marina or boatyard. In lieu of this ground-fault protection on the main, individual GFCI protection on each branch circuit or feeder was permitted.

For the 2017 NEC, this maximum 100 mA capacity has been reduced to a maximum of 30 mA. This 30 mA ground-fault limit is recommended in a report commissioned by NFPA’s Fire Protection Research Foundation. This report stated in part: “While 30 mA through the body is more than enough  to kill a swimmer (above the “let-go” threshold established for a Class A GFCI device), it is not sufficient to assume that all of the 30 mA leaking into the water will actually go through the swimmer. 30 mA represents an acceptable level to prevent a majority of electric shock drowning (ESD) incidents while remaining practical enough to minimize unnecessary tripping.”

Some users of the Code will argue that true protection for personnel (people) is only be achieved with Class A GFCI protection (maximum 4 to 6 mA current levels). This let-go level of protection would prove to be too sensitive for the wet environments encountered at marinas and docking facilities, resulting in continual “nuisance” tripping.

It should be noted that a related change occurred at 555.24 that calls for posting of signage to alert personnel coming into the vicinity of marinas and boatyards of the potential for shock hazards. See Article 555.24 in this publication for more information.