Shore Power Cord Problems

The photographs of the shore power cord and damage to the dock and boat were found as I arrived for a condition and valuation inspection for an owner that lived out of state. The inspection was requested by his insurance company, who apparently dodged a bullet.
As boating season winds down, our visits to our boats dwindle. Many of us live remotely from our vessels and over time we grow comfortable in their self preservation. Shore power systems are commonly found defective. Dock box circuit breakers are designed to prevent problems like this, but are notoriously unreliable.
By their nature shore cord connections are subject to weather, movement and wear. All of which increase resistance and thus temperature of the conductors.
Approximately one out of every five boats we inspect has some problem with the shore power system.
The most common problem is heat damage at the shore power cord or vessel connectors. No amount of heat damage to these components should be disregarded. A small amount of visible heat damage is often an indication of much more significant damage which is not visible. Think visible part of iceberg versus what is below the water.
Because of our involvement with damage claims, we investigate many vessel fires and work alongside origin and cause experts. Their conclusions are often that the fire was electrical in nature and initiated near the shore power inlet. While some of these fires have been localized to the vessel itself and even to just the shore power inlet area, some result in entire marinas going up in flames.
A few simple practical pointers.
Make sure all designed components for the connectors are present and functional. Shore power cords should have a means to secure the cord to the inlet and protect the conductors from weather. The shore power cord should have strain relief where necessary. If your cord dangles five feet from the inlet to the dock, strain relief should be used to eliminate the strain between the cord and the inlet.

A shore power cord should not look like these.
Always make and break dead connections. The circuit breaker at the dock should be turned off prior to connecting or disconnecting the shore power cord from the vessel. The circuit breaker should be turned back on only after the shore power cord connection has been made at your boat. This prevents arcing damage which will contribute to problems at the connector.
I am fond of a product called “Smart Plug”. The plug requires no twisting and has features which reduce several of the problems that we encounter regularly, but it is more expensive.
Besides fires, many problems are caused by shore power malfunctions. Regularly checking shore power connections is an excellent way to avoid these problems. Your boating neighbors can help.
Take a moment, like that time in church where you shake the hands of those around you, and meet your neighbors. In addition to challenging strangers you see aboard each others’ vessels, develop a mutual plan for checking shore power cords and exchange contact information, the boat you save could be yours.