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The Below Deck Unit BDU
Chapter 2
Standard Cable
connections
In addition to the DC power connection, an ignition sense connection must be made. This is
done using the three-wire power cable. In the case of a vehicle installation, the power source
is typically the vehicle battery. Cables should be routed appropriately, cable ties and clamps
should be used as required to ensure that vibration and/or rubbing of the cables does not
occur.
Ignition sense (white wire)
Route and connect the white wire (ignition sense) to a switched 12 or 24Vdc source,
such as accessory line or fuse block. Extended use of ignition sense in the accessory
position (ACC) by the end user may lead to a discharged car battery.
Note: Ensure that the connection is a switched source: OFF when ignition is off or in
start and ON only when ignition switch is in the ACCESSORIES or RUN position.
Note: If using the optional car adapter plug, the ignition sense wire is already
connected to the positive power wire in the plug.
Chassis grounding
The unit includes an isolating power supply. The BDU must be grounded by
connecting a 8 AWG grounding wire from the chassis ground point to the vehicle
chassis. See figure below. The ground wire should be clamped between the two nuts
ensuring both are securely tightened.
Chassis Ground
Point
