Wiring Color Codes
In the United States, commercial and domestic wiring follows a color code
established by the National Electrical Manufacturers Association (NEMA).
Three wires are used for standard 120 volt circuits. A black color is used for
the 120 volt "Hi side," a white wire is the "Low side," and a
green wire is used for earth ground. If you measure the voltage between the black
and white wires, you will measure 120 volts. If you measure the voltage between
the black and green wires, you will measure the same 120 volts. This is because
the white wire and green wires are connected together at the power distribution
transformer. Vessels built in the U.S. normally follow this three wire system.
The main shore cable also has a black, white, and green wire. The black and white
wires go to the vessel's main circuit breaker, while the green wire goes to the
vessel's ground buss.
Vessels equipped with polarity indicators can monitor the local dock power for
correct polarity. This can be quite helpful. Many older dock power outlets do not
follow the NEMA wiring code, and can be hazardous to you and your vessel. Some
foreign built vessels do not follow the NEMA code either. In fact, we have seen some that are genuinely confusing, even to the point of changing from one color to another along the length of the wiring harness.
The output winding on the EW-4200D generator is not grounded to
the frame (earth ground). We provide a two wire system; a black "Hi side,"
and a white "Low side." Electrically, the output is "floating"
and has no reference to the "earth."
If you wish to establish an earth ground reference for the generator output,
add a jumper wire from the white wire "Low side" to the chassis of the engine
generator. Then, connect a green earth wire from this new point to the vessel's
A proper system should include a "ship/shore" switch so the vessel can
be powered from either shore power or generator power. This is a special switch
used to disconnect the vessel's main breaker from the shore power cable and
connect it to the generator, and vice versa.
Connect both the black "Hi side" and the white "Low side"
wires to a set of "input" terminals on the switch. Disconnect the shore
power cable from the master circuit breaker, and reconnect it to the other set
of "input" terminals on the switch. The "output" set of
terminals is then connected to the master breaker. Some vessels have split
systems with two shore power cables. If you have this arrangement, call us for a
technical consultation and we will explain your options. If you have, or plan
to install, a D.C. to A.C. inverter for occasional A.C. power, you may also
wish to call us for a technical consultation.
The generator is rated for 35 amps output, so a 35 amp (or lower) circuit
breaker should be installed in the A.C. circuit for generator protection.
12 Volt D.C. Battery Connections
The starter motor on the engine draws approximately 60 amps during cranking.
Use wire equal to or greater than #4 gauge. The +12 volt terminal on the
starter motor will accept a 3/8" ring type wire terminal.
The -12 volt battery cable connection can be made to the engine bracket bolt on
the left front side of the engine. A 3/8" ring terminal will fit the bolt.
Typical starting time is 3 to 7 seconds for a properly operating engine. This
translates into 0.1 ampere hour of power. The D.C. current demand by the unit
during normal operation is only 1 amp; therefore, it is practical to draw power
from the ship's main engine battery. Connection can be made at either the
battery switch or the engine. If a separate battery is to be dedicated to the
generator, a small trickle type battery charger can be used to keep the battery
fully charged. A charger capacity of 1 amp is more than adequate. It should be
noted, that since the unit only requires 1 amp of D.C. power to operate,
hand crank starting in an emergency can easily be accomplished. Even though the
battery may not be able to turn the engine over, it will almost always have
sufficient reserve to provide 1 amp for running. A couple of 6 volt lantern
batteries, connected in series, will also provide the power needed.