Marine Electrical Products
AC Rotary Switch Panel
2 Positions + OFF, 3 Pole
PN 8363
Switches 2 - 120/240 V AC Sources
Compact solution when circuit protection is provided elsewhere
Allows connecting one of two different AC sources to one circuit
Heavy duty industrial rated switches
Intuitive function - One handed operation
Green power available LED indicators
Red reverse polarity LED indicators
UL listed switches
Panel Specifications
Voltage Rating:
Panels are rated for 120 volts AC
Amperage Rating: 65 amp maximum service
Panel Material:
0.125” 5052-H32 Aluminum Alloy
Primary Finish:
Chemical Treatment per Mil Spec C-5541
Final Panel Finish: Graphite color 2 part textured Polyurethane
Maximum Wire Size:
Minimum Wire Size:
12 AWG
Terminal Recommended Torque:
40 lb-in.
Overall Dimensions:
Mounting Centers:
Mounting Depth:
5-1/4 x 3-3/4
4-7/16 x 2-15/16
It is not possible within the scope of these instructions to fully acquaint
the installer with all the knowledge of electrical systems that may be
necessary to correctly install this product. If the installer is not
knowledgeable in electrical systems we strongly recommend that an
electrical professional be retained to make the installation.
If either the switch front or back is to be exposed to water it must be
protected with a waterproof shield.
The switch must not be installed in explosive environments such as
gasoline engine rooms or battery compartments as the switches
are not ignition proof.
The vessel’s shore power cord must be disconnected form shoreside
power before installing this electrical switch.
If an inverter is installed on the vessel its power leads must be
disconnected at the battery before the panel installation. Be aware that
many inverters have a “sleep mode” in which their voltage potential
may not be detectable with measuring equipment.
If an AC Generator is installed aboard it must be stopped and rendered
inoperable before the switch is installed.
Verify that no other AC or DC source is connected to the vessel’s
wiring before the switch is installed.
Any Blue Sea Systems product with which a customer is not satisfied
may be returned for a refund or replacement at any time.
133.35 x 95.25
112.71 x 74.61
Blue Sea Systems Inc.
425 Sequoia Drive
Bellingham, WA 98226 USA
Document 6632 Rev.B
Phone (360) 738-8230
Fax (360) 734-4195
E-mail conduct@bluesea.com
The switch provides switching, but does not provide circuit protection.
It is not a substitute for a main circuit breaker.
Disconnect all AC and DC power
Disconnect all AC power originating on or off the vessel. This includes
inverters, generators, shore power attachments and any other device
capable of supplying AC power to the ship’s circuits.
Wire sizing chart
Use the wire sizing chart below to determine the minimum branch and
feed circuit wire sizes.
Disconnect the main positive DC cable from all batteries to eliminate
the possibility of a short circuit and to disable the inverter while
installing the switch.
Select mounting location and cut opening
Select a mounting location which is protected from water on the front
and back of the switch and is not in an area where flammable vapors
from propane, gas or lead acid batteries accumulate. AC rotary
switches are not ignition protected and may ignite such vapors.
Using the panel template provided, make a cut out in the mounting
surface where the distribution panel is to be mounted. Do not yet
fasten the panel to the mounting surface.
Install source 1, source 2 and output wires
Install the feed wires from AC Shore Power and AC Generator. Install
the output wires. Refer to the wire sizing chart to select the minimum
wire size. Connect wires as shown in the illustration. To avoid excess
wire temperatures when cooling may be limited, we recommend using
at least 12 gauge wire for 30A and 8 gauge wire for 50A.
Do not confuse the neutral current carrying wires (sometimes called
ground) with the green normally non-current carrying wires (sometimes
called grounding). These two wires must be connected only at the
source of power, nowhere else.
A double pole circuit breaker must be installed within 10 feet of the
shore power inlet, ahead of this switch. The measurement is made
along the conductors.
Testing Connections
It is very important that the wiring be connected according to the
diagram. The line and neutral from each source must be paired
together and not connected such that the switch selects line from one
source and neutral from another. Verify the connections and see that
each connection is securely tightened, including the terminals for the
jumpers installed on the switch where no wires are attached.
It is possible to verify the connections using an ohmmeter before power
is applied. These procedures take a little time, but are recommended,
especially if some elements of a previous installation might not have
been properly labeled or followed the expected color codes.
Installation (continued)
Test Shore Connection to Switch
Disconnect the shore power cord from the shore power source
and bring the shore plug aboard to a point close to the switch
panel. Connect the other end of the shore cord to the boat’s
power inlet. Turn ON the shore power circuit breaker between the
inlet and the selector switch. Set the selector switch to OFF.
a. Use an ohmmeter to check for continuity from the shore
ground plug to the green wire at the electrical panel.
b. Check for continuity from the power cord plug neutral
pin to the neutral wire at the selector switch. [7]
c. Check for continuity between each line pin of the shore
plug and the line wire at the selector switch. [3], [11]
d. Check that there is a high resistance between (>1000
Ohms) the neutral conductor and the grounding
e. Verify that there is a high resistance between (>1000
Ohms) between the shore cord plug neutral pin and
each line pin. There may be indicator lamps in the
circuit, but no more than that with the selector switch in
the off position.
Testing Performance
Test Shore Power
Verify Switch Selects Shore Input
With the shore cord still disconnected from the shore and
available onboard, and the generator set not operating, set the
load circuit breakers to off, so there is no load at the output side of
the selector switch.
a. Verify that the there is a high resistance between each
line and neutral of the load side terminals of the
selector switch. There may be indicator lamps still
attached, so it may not read open circuit. [2] to [6], [6]
to [10]
b. Set the selector switch to SHORE. The ohmmeter
should still indicate a high resistance, for the same
c. Short each line pin to the neutral pin of the shore cord
and verify that each line and neutral at the load side of
the selector show a low resistance when these are
shorted and a high resistance when they are not.
Verify the Generator Wiring
Turn the generator circuit breaker to OFF and set the selector
switch to the generator position. All load circuit breakers should
still be off. Leave the shore input circuit breaker in the on
a. Verify that there is a high resistance (>1000 Ohms)
from each line to neutral. [2] to [6], [6] to [10]
b. Verify that there is a low resistance from the neutral to
ground at the load connections. [6] to [ground]
c. With the generator still not running, close the generator
circuit breaker at the generator. Verify that there is a
now a low resistance from each line to neutral where
the generator windings are now connected across the
d. Verify that there is still a high resistance from neutral
to ground and neutral to each line at the shore power
Set the Selector switch to OFF, turn the shore power breaker
to OFF, and leave the load panel circuit breakers in the OFF
Set your multimeter to volts.
Apply circuit labels and mount panel
Apply a label for the circuit form the 10 basic labels provided. If the
appropriate label is not included individual labels are available form
Blue Sea Systems for specific applications. Refer to the label order
form included with the panel for a complete listing of individual labels.
Fasten the panel to the mounting surface using the panel mounting
screws supplied with the panel.
Connect the shore power cable to the shore power source. Turn
on the shore source to make power available to the boat.
a. Turn the selector switch to SHORE. No Reverse
Polarity lights should be lit, and power available should
be indicated. If any red Reverse Polarity lights are on,
turn off the shore power circuit breaker and disconnect
the shore cord at the shore source. Either the hot and
neutral or hot and ground wires have been reversed.
Starting at the distribution panel, trace the connections
as far back as necessary to locate the error.
b. If there are no indications of reverse polarity, check to
see that power is available. If the electrical distribution
panel has a meter, verify that shore power is available
and at the proper voltage. If there is no meter, turn
on the load circuit breaker for an AC circuit powering
a convenience outlet and use a voltmeter to verify
that power is available from line to neutral at the plug.
Verify that there is no voltage between ground and
Test Generator System
Turn the circuit breaker at the shore source to OFF. Set the
selector switch to OFF. The shore power available lights should
all be off. Start the generator and turn the generator breaker to
a. The power available light for the generator output
should light. The reverse polarity light should be off.
b. There should be no power available indication at the
shore power circuit breaker.
c. Set the selector switch to GENERATOR. Power
should be available at the power distribution panel. If
the electrical distribution panel has a meter, verify that
power is available and at the proper voltage.
d. There should be no power available lights indicating at
the shore circuit breaker, or the shore indicator of this
The Purpose of the AC Main Source Selector Panel
Alternating Current (AC) power changes polarity 60 times per second in
the US, Canada and Latin America and 50 times per second in Europe.
This is the frequency of the power and is referred to as Hertz (or the now
outdated term “cycle”). Because of this alternating nature of AC power,
two live sources of AC power, such as shore power and inverter power,
or shore power and a generator, cannot be electrically connected. The
AC Main Source Selector panel is designed to connect two sources of
AC power to a common circuit while preventing both sources from being
connected to the circuit simultaneously.
Related Products from Blue Sea Systems
High Amperage Fuses and Circuit Breakers for positive feed wires
High Amperage Battery Switches
Terminal Blocks and Common Bus Connectors
AC Distribution Panels
DC Distribution Panels
AC and DC Digital and Analog Voltmeters and Ammeters
Useful Reference Books
Calder, Nigel, 1996: Boatowner’s Mechanical and Electrical Manual,
2nd edition, Blue Ridge Summit, PA: TAB Books, Inc.
Wing, Charlie, 1993: Boatowner’s Illustrated Handbook of Wiring,
Blue Ridge Summit, PA: TAB Books, Inc.
Installation (continued)
Wiring Diagram
AC Source Selector Panel
PN 8363 Shown
Panel Template
AC Source Selector Panel
PN 8363
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