13
Plan and install an NMEA 2000
®
network
An NMEA 2000
®
network consists of a powered backbone from which drop cables connect to
NMEA 2000
®
devices. The backbone needs to run within 6 m (20 ft) of the locations of all products
to be connected, typically in a bow to stern layout.
The following guidelines apply:
• The total length of the backbone should not exceed 100 meters (328 ft).
• A single drop cable has a maximum length of 6 meters (20 ft). The total length of all drop
cables combined should not exceed 78 meters (256 ft).
• A terminator must be installed at each end of the backbone. The terminator can be a
terminator plug or a unit with a built-in terminator.
A
A
A
A
C
C
D
B
B
B
B
E
Power the NMEA 2000
®
network
The network requires its own 12 V DC power supply, protected by a 3 A fuse.
For smaller systems, connect power at any location in the backbone.
For larger systems, connect power at a central point in the backbone to balance the voltage drop of
the network. Ensure the load/current draw on each side of the power node is equal.
¼
Note:
1 LEN (Load Equivalency Number) equals 50 mA current draw.
4
LEN
(8 LEN)
(8 LEN)
T
T
2
LEN
2
LEN
3
LEN
1
LEN
3
LEN
1
LEN
¼
Note:
Do not connect the NMEA 2000
®
power cable to the same terminals as the engine start
batteries, autopilot computer, bow thruster or other high-current devices.
A
NMEA 2000
®
device
B
Drop cable
C
Terminator
D
Power supply 12 V DC
E
Backbone
