What You Should Know About Ground Faults

Ground Faults

Ground faults often go undiagnosed by boat owners. Find out more and check out our promotion!

Ground faults are a surprisingly common problem that also tend to mystify plenty of boat owners. It’s caused by current leaking from the AC hot or neutral conductors to ground because of faulty insulation, failing appliances or other electrical devices, or improper wiring. Compared to typical home or commercial wiring or equipment, electrical systems on boats are more complicated—so as a boat owner, it’s important to understand what issues may impact your systems and what you can do to fix it.

Several years ago, the National Electric Code changed and required marinas to install ground fault protected breakers at each slip. Many vessels have ground faults that have been asymptomatic for years, but as soon as they encounter a GPF protected dock they suddenly find they can’t plug into shorepower resulting in a ruined weekend.

Potential Causes of Ground Faults

As mentioned, many appliances or electronic devices can cause ground faults on your boat. There are a few more causes though, that include:

  • Household appliances. Be sure to use marine rated appliances, or have an ABYC electrician modify any appliances you use for marine purposes, otherwise you’re running the risk of creating electrical problems.
  • Second generation Galvanic Isolators, typically manufactured from 2002 to 2008. These units perform a self test by creating and measuring a ground fault. At the time, marine shore power services did not have ground fault sensors, which is why impressing a ground fault wasn’t as much of a concern.
  • Water heater elements or air conditioning compressors. As these items age, the insulation breaks down and can create a ground fault.
  • A neutral-ground connection somewhere on the vessel. Since electricity will take ALL available paths back to its source, if there is a connection between the ground and neutral buss’s anywhere onboard the vessel, this will create a ground fault.
  • Dryers. Speaking of neutral- ground connections, we have often found improperly wired dryers to be the source of this connection. In a pinch for time, many boat owners and inexperienced techs won’t bother to read the directions and will not adjust the wiring for a 4 wire installation. This leaves the case of the dryer connected to both the neutral and ground wires creating a ground fault onboard.

Tips for Troubleshooting

To begin, turn of all AC breakers and unplug your boat. Plug the cord into the pedestal but leave it disconnected from your boat, then turn the power on. If this causes it to trip, this means the cord is most likely the culprit. If not, connect the cord to the boat but leave any onboard breakers off. Turn the power on at the pedestal and take note of whether or not the ELCI trips. If it does, you cannot safely use the boat and must contact an ABYC certified electrician. If it doesn’t trip, continue by turning on each breaker one by one. Once you find the load causing the fault, leave the breaker off until a repair is able to be made, though the boat can be safely operated until then. An important tip: faults are often on cycling loads, meaning you must wait a few minutes between checking breakers to help isolate these faults.

Our Summer Ground Fault Promotion

Boating season is short enough as is so don’t let a hidden ground fault ruin a weekend on the water. Bring the boat in anytime we are open M-F 8-5 (please call ahead), and we will run a dockside test to see if your boat presents a ground fault that would trip a GFP breaker at a protected marina. If we find a fault, our ABYC certified techs can make a repair in your down time so you don’t have any surprises when you visit your first GFP protected marina.

Reach Out to Tidewater Today!


If you’re in the greater Baltimore area and are in need of boat services, contact Tidewater Yacht Service at 410-625-4992 or by email at info@tysc.com. Our location is at 321 East Cromwell Street Baltimore, MD 21230. Get in touch with us today! Whether you need hauling, systems repaired, or storage, we have the experience and expertise to help. We’ve been providing our services to the Chesapeake Bay for over 30 years and know how to properly handle your vessel with care.


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This entry was posted on Friday, July 6th, 2018 at 10:28 am. Both comments and pings are currently closed.