Pre-Purchase Inspections
July/August 2009 - GFCI Receptacles

The convenience of plugging a coffee maker, hairdryer, microwave oven or cell phone charger into an AC receptacle aboard your boat is hard to beat. Whether the energy it supplies is derived from shore power, a generator or an inverter, the "always on" aspect of electricity afloat is a virtual expectation these days, and why not? It's the rare cruising vessel that's not equipped with an inverter and most have generators too, making it possible to effectively take shore power with you where ever you go. However, even if your vessel is equipped with the most rudimentary AC system, the standard for electrical safety remains high. Because the marine environment presents greater opportunities for electrical faults, guidelines have been established to minimize the risk.

One of those standards calls for the installation of Ground Fault Current Interrupter receptacles, also known as GFCIs in areas whose risk for shock or electrocution is high; these include the galley, head, engineering spaces and weather decks. Most residential and commercial building codes mandate the use of these receptacles in similar locations ashore. GFCI receptacles are inexpensive, usually about $15. While that makes them economical enough to use throughout the vessel, one GFCI receptacle is capable of providing protection to several ordinary receptacles, making it tough to argue for anything other than vessel-wide protection. Simply put, one would be crazy to not take advantage of this inexpensive life saving device. Yet, the owners of many cruising vessels I encounter unwittingly do just that.

The image shown in this month's ad, taken aboard a vessel undergoing an SDMC Pre-Purchase Inspection, shows an engine room mounted AC receptacle. The test instrument display indicates that a simulated fault current of seven milliamps (the approximate threshold for protection of people) has been applied for six and a half seconds, the maximum duration of the test and well beyond the typical GFCI trip time, which typically lasts no more than a few thousandths of a second. This means the receptacle lacks ground fault protection and therefore represents a shock or electrocution hazard; it would only take a frayed extension cord, a damp droplight, drill or vacuum to create such a scenario.

If you’re interested in finding out more about pre-purchase inspections, vessel selection assist, the Captains’ Club (simply click on these words to be taken to the relevant sections of this website) or other services offered by Steve D’Antonio Marine Consulting, send an email or call 804-776-0219.