How to Wire a Marine Inverter

Televisions and refrigerators can come to sea with an inverter.

Marine inverters can make life afloat a little more comfortable by allowing you to bring some of the comforts of home out on the water. The inverter lets you operate a TV or other household appliance on your boat and even serves as a battery charger. It also represents a serious electrical hazard if installed improperly. The inverter you choose should be ignition proof--its construction must prevent the ignition of fuel vapors around it by sparking or its external temperature.

Things You'll Need

• Adjustable wrench
• Cables
• Ring type terminals
• Pliers-type wire crimper
• spray vinyl electrical insulation
• vinyl insulating covers
• Soldering gun
• Silver core solder
• Warning placard or sign

Instructions

1. Mount the power inverter in a location where it can be seen, using the mounting bolts supplied with the inverter and an adjustable wrench. A power inverter that's located in an obscure place in your engine room is an invitation to trouble. Find a location as close as possible to your batteries, preferably one visible from the breaker panel, and bolt the inverter down securely to prevent its movement in rough seas.

2. Crimp ring type terminals to both ends of the negative cable and one end of the positive cable, with a pliers-type wire crimper. Cover the joint with spray vinyl electrical insulation or insulating covers. The cables should be at least the size of your battery cables.

3. Solder one wire of an inline fuse holder/fuse of the same amperage as the inverter to the free end of the positive cable with a soldering gun and silver core solder. Solder the free wire of the fuse holder to a second piece of positive cable less than 6 feet long. Crimp a ring connector on the free end of the 6-foot piece of cable. Cover the solder/crimped joints with a vinyl insulator.

4. Remove the connection nuts from all battery posts and the positive and negative posts on the inverter. Connect the positive cable--with the inline fuse--from the positive post of the inverter to the positive post of the first battery in your battery bank and thread the connection nuts onto the posts at least hand tight. Connect the negative post of the first battery to the positive post of the second battery and secure the connection nuts. Connect the negative post of the second battery to the negative post of the inverter and secure the connection nuts. Ground the inverter according to the instructions that come with the individual inverter.

5. Put a warning on the breaker panel that states that your electrical system includes an inverter, so that anyone troubleshooting your electrical system is aware of the inverter's presence and operating mode. As National Marine Manufacturers Association inspector Tim Pitts said in an interview in "Seaworthy" magazine, "Inverter AC voltage will make you just as dead as AC voltage from shore power."

Tips & Warnings

• Be sure that the inverter you choose has an indicator light that lets you know when the inverter is operating.

• Never use wire nuts in your engine room or aboard your boat. Wire nuts have an open bottom that will collect condensation, lead to corrosion in electrical connections and ultimately cause a fire aboard your boat.

• Never locate your power inverter above your batteries. Battery gassing causes corrosion in electrical equipment and, like wire nuts, leads to fires.

References

• "Seaworthy Magazine;" Boat Projects Gone Awry; April 2010