[CA] [CA11] New installation multiple power inputs

[pfrank]

I have searched the forums and could not find a ready answer, so please forgive me if this is old news.

I recently had a Raymarine dealer install a new Evolution autopilot system, a p70 control head, a wheel pilot and an Axiom 9 to my 1995 32' sailboat . Since these were the first modern electronics on the boat (although my existing ST60+ Wind and Tridata instruments were integrated into the new system), the dealer installed both SeaTalkng and NMEA 2000 networks (which were interconnected).

Contrary to what I see in manuals and on these forums, the dealer installation included multiple power supplies to the networks. Fused power circuits were connected to 1) the ST60+ Wind (which was daisy chained to the ST60+ Tridata which was then connected to the Seatalkng backbone through an E22158 converter), 2) to the Seatalkng backbone itself, and 3) to the NMEA 2000 backbone itself.

To experiment, I pulled the fuses for both NMEA 2000 backbone and the ST60+ Wind and everything on the network still apparently works as it should. This seems to verify that I only need ONE power supply for the network (even if it is an interconnected SeaTalkng and NMEA 2000 network) AND the ST60+ instruments also get their power from the network as well.

My questions are:

A) Is there a reason why my dealer/installer would provide multiple power inputs as described?

B) What harm occurs from having multiple power inputs as described?

C) The power input to the NMEA 2000 backbone is an open circuit when the fuse is pulled. Should I pull that power cable off of its backbone connector and replace with a NMEA 2000 terminator?

Thanks!