NMEA 2000 devices with other electrical interfaces have internal isolation between device power and network power.

• A. False
• B. True
• C. Depends on device
• D. Not specified

Answer: (B)

The idea being tested is that there is electrical isolation between a device’s own power and the NMEA 2000 network power when the device also has other electrical interfaces. This isolation helps prevent fault currents, ground loops, or voltage differences from the device’s non-network power from feeding onto the CAN-based NMEA 2000 bus. By keeping the network power domain separate from the device’s internal power, devices that integrate other interfaces (such as USB, Ethernet, or analog I/O alongside NMEA 2000) can be powered from different supplies without compromising the bus’s operation or safety. That’s why this statement is true: isolation is provided to protect and stabilize the network when mixed interfaces are present. The other options would imply no standard isolation, dependence on the device, or lack of specification, which aren’t aligned with how NMEA 2000 handles mixed-interface devices.