The maximum voltage drop from the battery source to the power insertion point is:

• A. 3%
• B. 3.5%
• C. 2%
• D. 5%

Answer: (A)

In NMEA 2000 installations, voltage drop along the power path from the battery to where the power is inserted must be kept small so devices always see enough voltage. The standard limit for this drop is 3% of the system voltage. For a typical 12-volt system, 3% is about 0.36 V, so the voltage at the power insertion point should be roughly 11.6 V or higher under load. This helps ensure the network operates reliably even with wiring resistance and connectors.

Choosing 3% as the limit reflects a balance between practical wiring considerations and ensuring devices stay within their acceptable voltage range. The other percentages are not the stated limit, and a larger drop (like 5%) could cause devices to underrun, while a smaller drop would be stricter than the standard.