connecting power to new network

[Chuck - Raymarine - Moderator]

Nate,

Q1) What amperage breaker should I attach to the backbone power cable? I didn't see any guidelines anywhere and the equipment is described variously as watts, amps, or no description. If that question takes us beyond the forum bandwidth is there anything you could direct me to?
A2) Per the SeaTalkng Reference Manual, the SeaTalkng circuit must be protected by a 5 A fuse or a circuit breaker providing equivalent protection.

Q2) I looked at the chart you referenced in another post on LEN values but didnt see the transducers, the Sonar or the RADAR. I couldnt find that info in the docs either. So I don't have LEN values for the transducer (DST800), the radar (Quantum with direct connection to eS127), the sonar (P79 Raya with direct connection to eS127), or the two MEFI's from Fox Marine (By the way, thanks for the info on the MEFI's you directed me to. That was helpful.) I assigned a LEN value of 1 to each just to see how balanced the network was and it came back to 8 and 8. Without LEN values for them one side is off by 1. Should I assign LEN values to them? May have answered my own question here.
A2) LEN (Load Eqivalency Numbers) are only applicable to devices are fully powered by the backbone (ex. Raystar 130 GPS Sensor, iTC-5, instrument displays, smart transducers, etc.) or have SeaTalkng communications interfaces which are powered by the backbone (ex. MFDs, autopilot ACUs, etc.). Accordingly, only devices which have been directly interfaced as spurs to a SeaTalkng backbone need to be considered. As only the only the communications interface of a MFD is powered by the SeaTalkng backbone the MFD will have a LEN of 1, irrespective of whether it has been interfaced to a fishfinder transducer or radar transducer.

Q3) This question has to do with powering equipment. If I don't connect a switch to the backbone power cable, will the P79 continue sounding with the eS127 powered down?
A3) When the MFD is powered OFF, the P79 fishfinder transducer will no longer ping.

A4) Will the DST 800 continue measuring temperature and depth with the I70s powered down?
A4) Yes.

Q5) when I switch off the equipment (using remote switches) will I lose any set up data for any of the equipment?
A5) No