In a voltage drop calculation for a small network using Lite Cable with Backbone Length 20 meters and LEN 11, what is the voltage drop?

• A. 1.25 volts
• B. 0.75 volts
• C. 2.50 volts
• D. 0.125 volts

Answer: (A)

Voltage drop on a NMEA 2000 Lite Cable network comes from the resistance the current must travel through along the path from the power source to the loads. The backbone length and the LEN value determine how much conductor is in the current’s path, so they directly affect the total resistance the current sees. The longer the path and the more load distribution along it (represented by LEN), the greater the voltage drop for the same current.

In this problem, with a Backbone Length of 20 meters and LEN of 11, the Lite Cable resistance along the route, combined with the expected network current, yields a voltage drop of 1.25 volts. So the far end would receive about 12 V minus 1.25 V, i.e., around 10.75 V, which is a typical outcome for this setup.

The other numerical options would correspond to either too small or too large a drop for the same inputs, so they don’t match the calculated result given these parameters.