There was an
electrical fire a one of my favorite
marinas. Posted in the aftermath and I had to share:
Shore power Cord 101
At the
dock:
Always turn off the
power before connecting or disconnecting your cord.
Inspect dockside power receptacles for damage before you
plug in.
If the cord end falls into the
water, wash it with freshwater, dry it and then spray it with a water-dispersing spray such as CRC 6-56.
Additionally, spray corrosion-blocking spray into the blade sockets every time you
plug into a new power post.
At the
boat:
Use dielectric grease on the
hull inlet blades.
Always use the locking ring at the
hull inlet and on any adapter fitting.
Always screw the hull inlet cover tight when the cord is unplugged from the
boat.
Check the temperature of the cord ends several times a year.
Saltwater effect on Connectors: The residual saltwater around the blades is transferred to the power post receptacle. As the
water dries out,
salt crystals remain. These cause
corrosion.
Corrosion is like friction in the
electrical circuit. It causes resistance, resistance creates heat, and the corroded connector heats up.
Turn off breaker before disconnecting and connecting: Have you ever connected or disconnected your power cord without turning off the power at the breaker? If so, each time you do this you draw an
arc which burns a spot on both the receptacle and blade. Arcing burns are not conductive and also cause resistance, and therefore heat, in the connection. The
heating and
cooling can loosen the screws holding the wires in the
dock receptacle. Loose wires mean poor connections, high-resistance connections and more heat.
What to Check: Over time corrosion and arcing slowly but surely degrade the electrical contacts. Your first indication of something going on a cord end that feels warm to the touch. If the connections are clean, the end of the cord will run at the ambient temperature of the surrounding material. An infrared thermometer is the best tool to
monitor the connection (you can buy one of these online for as little as $20). As time goes by the corrosion gets worse, and the resistance in the cord end climbs to the point that the receptacle is overheated and damaged.
When you get ready to plug into a power
pedestal, be sure to switch the breakers off at the
shore power post and at your boat’s AC panel. Then look at the
shore power pedestal.
When you use an adapter at a power pedestal, use the connector ring and lock the cable to the adapter so you don’t leave a gap.
Use of Dielectric grease on your plug blades are a good practice to prevent moisture and corrosion.
All these things are good practice no matter where you take your boat. I hope this helps each of you and prevents future incidents.
On a final note, and this may seem obvious, however, be sure to always use the appropriate power cord to power your vessel.