The electronics on my boat associated with the NMEA-2000 network are Simrad EVO3 and NSX multi-function displays, an autopilot (with a Precision 9 GPS compass, NAC-2 controller, and AP-44 head), a NEP-2 Ethernet Network Expansion Port, a Halo 20+ radome, Fuel Data Manager module, a Sirius WM-4 weather satellite receiver, a Standard-Horizon 2400 VHF Marine Band radio, and a Fusion MS-205 entertainment radio. Some devices are also networked with Ethernet.
My goal with regard to providing power to the NMEA-2000 network was to use a simple switch that controlled the 12-volt power from a fuse block sub-panel; this would allow me to power down non-essential items when the engine was not operating, only keeping the chart plotters, the radar, and both the VHF Marine radio and the entertainment radio powered on.
To control power to the NMEA-2000 network I used a BLUE SEA SYSTEMS lighted push button switch.
There were several problems:
[list][*]the switch illumination would never turn off completely nor display the right color; the illumination was supposed to be BLUE when the switch was off and RED when the switch was on;[*]disconnecting the network power from the sub-panel would result in some [network devices remaining] powered up;[*]transmitting on the VHF Marine Band radio at 25-Watt power caused the [network] power to shut down;[*]transmitting at 1-Watt would not shut down the [network] power.
I contacted Blue Sea Systems. They told me the switch I was using was discontinued [due to internal contact leakage] and was now replaced with a newer model [without any internal contact leakage]. Blue Sea Systems sent me a new switch. The new switch had a slightly larger mounting hole--there was already a big hole in the center of my dashboard.
- Fig. 1. A dashboard switch around which a red circle has been drawn to draw attention to the switch.
- WC_switch.jpeg (37.36 KiB) Viewed 2276 times
The new switch had almost identical problems: the switch illumination was not working correctly; it was only a red LED when powered on.
I was frustrated to the point that I installed a simple ON-OFF switch, fed from a separate 12-Volt source [to control power to the network]; this change was a clue to look elsewhere [for the cause of the problems]: [leakage in the BLUE SEA SYSTEM switch controlling power to the network was not the cause of the problem because the problem remained with the simple ON-OFF switch].
On the FUSION MS-205 radio there two different NMEA-2000 interface cables available, one black and one red: if a black cable is used then the radio DOES NOT power the attached network; if a red cable is used, the radio DOES power the attached network. When installing the FUSION MS-205 radio, the red powered NEMA-2000 port cable should not be used [if connecting to an already] powered network.
The boat manufacturer installed [the FUSION MS-205 so it was powering the network, that is, with the red cable]. The network power was like this for six years with no problems.
Even when the FUSION MS-205 radio power switch was set to OFF, the FUSION radio was still feeding power to the network backbone. And through the backbone the radio was powering some of the devices, even when [the other source of network power via the switch was OFF. Also an LED [on the BLUE SEA SYSTEMS illuminated switch was ] dimly illuminated. I didn't think this was possible.
One fix was ordering [the special black drop cable with blocked power; this was as going to take several weeks. The alternative was to buy and use an NMEA-2000 power isolator in the [red] drop cable between the FUSION MS-205 radio and the network backbone.
I installed a power isolator; all is now good.