The Mini Powertap has 4 connection points. There are two 5-pin connectors on opposite sides of the powertap that are used as the NMEA 2000 bus connections (marked "BUS"), there is a 4-pin connector on the bottom of the powertap that is used as the power connection (marked "Supply"), and there is a threaded stud with bolt connection for the shield connection. The yellow powertap cable, which plugs into the 4-pin connector found on the bottom of the powertap, is connected to an appropriate 12 volt DC power source. The color coding is as follows:
The powertap is capable of handling 16 amperes -- 8 amperes for both NMEA 2000 bus connections.The Schottky diodes are used to isolate the power supply connected to the powertap from other power supplies connected elsewhere on the network.
Notice that the powertap has two internal 8 ampere fuses, which should be checked if bus power on either side of the powertap is not available (there are two extra fuses under the cover). These fuses help protect one side of the network when there is a power supply short circuit on the other side of the network. In other words, the whole network doesn't come crashing down with a short circuit between +12VDC and Ground. All the components on the opposite side of the short circuit stay up and running.
Image of NM4P-NF with cover removed to expose fuse connections:
Article Number: 471
Posted: Wed, Jul 7, 2010 4:03 PM
Last Updated: Mon, Jul 27, 2015 6:36 PM
Online URL: https://www.maretron.com/support/knowledgebase/phpkbv7/article.php?id=471