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DREAM CATCHER OPERATING MANUAL
NW Explorations
4F5: AC Power Selector Switches
The lower AC panel to the right of the lower helm wall has three
selector switches:
“GENERATORS SELECTOR”
This switch determines
which generator
is supplying power, if
any... “AC POWER SELECTOR”
This switch determines whether (1) the generator selected by the “Generators Selector” is supplying the boat,
or
(2) the
shore power inlet selected by the “Shore Power Selector is supplying the boat...
“SHORE POWER SELECTOR”
This switch determines
which Shore Power receptacle
is supplying power, if any.
4F6: AC Reverse Polarity Indicator
Although we tend to think of AC Electricity as having only two conductors, it actually has three. One of these is called
“neutral”; one is “hot”; and one is “ground”, that is, it is supposed to be the same as the water around the boat and
the earth ashore. The vessel and many of its appliances rely upon these connections having the correct “polarity”, or
relationship to one another and the earth; this is essential to be sure that users of AC equipment do not get a shock
when touching and AC equipment.
Now in a house ashore, it’s easy: We don’t “plug in” the house, for it stays connected to the utility company all the time!
But in a boat when in the harbor, we do plug in using our Shore Power cords (and sometimes using extension cords). If
the outlet to which we plug our cord or if the cord itself is mis-wired, then these connections can become mixed up, and
there is a significant chance of getting a shock or a chance that running gear outside the boat will be subject to corrosion
because the boat, immersed in sea water, a good conductor of electricity.
To protect the vessel and its crew from such contingencies, a “Reverse Polarity Warning” light on the lower Generator
Control Switch Panel will illuminate when the connection turned on.
If any “Reverse Polarity” light should illuminate when connecting to Shore Power, immediately disconnect the cable and
contact the harbor master advising him/her of the problem. Do not risk shock or system damage!
The “Push to Test” button should light the “reversed polarity Bulb” to test it.
4F7: AC Shore Power, Disconnecting & Connecting
The large selector switches on the AC metering panel are used to determine the source of AC power for the boat (see
above). At least one of these switches should be “OFF” whenever you are connecting or disconnecting the boat to shore.
This is true so that you do not draw an arc from the plug due to the load of the boat on the connector’s pins: such an arc
will burn the contacts and eventually cause them to overheat when in use, creating a fire hazard.
Once connected to shore power, monitor the AC voltmeter and ammeter — both circuits — to be sure you have not
overloaded the circuit.
Important Note: If the house batteries are low when you first hook up to shore power, and the inverter is turned on (as
it should be), the inverter will begin charging its batteries at a very high charging rate, drawing a lot of shore power
current. Until this demand reduces (see “The Inverter System” below), you should turn “OFF” other high-current AC
appliances such as the water heater.
You can then turn on AC appliances as needed. Watch the ammeter to be sure you don’t exceed the dock’s available
supply, typically 30 amps.