What is the maximum drop length of a heavy NMEA 2000 cable?

• A. 4 meters
• B. 6 meters
• C. 8 meters
• D. 10 meters

Answer: (B)

In NMEA 2000 networks, each device connects to the main trunk with a drop. The length of that drop is limited to protect signal integrity and reliable power delivery across the whole network. For heavy gauge NMEA 2000 cable, the standard sets six meters as the maximum drop length. This limit helps keep the total network impedance and voltage drop within what the CAN-based bus can tolerate, ensuring devices receive enough voltage and the data signals stay within required timing and voltage ranges. If the drop is longer, voltage drop and added impedance can cause devices to misread data or fail to operate properly, especially when multiple devices are attached and the trunk is already carrying the bus load. So six meters is chosen to balance practical device placement with reliable network performance.