Per the TZtouch install manual it says " Do not mount on the overhead".
Honestly, I don't know why. The provided bracket will flip and work as an overhead mount. I think it has to do with another thing they point out in the install manual. "Mount where shock and vibration are minimal (to comply with IEC 60945 Ed4)"
It looks like it is to comply with a IEC standard. I will ask how important that this restriction be followed and get back with you. I can say, I have seen many overhead installs and haven't heard of any issues.
If I mount on overhead - can I just run 1 Ethernet cable to unit, and supply both dff1 hd & nmea 183 through it with use of a hub (looking to avoid multiple cables through piping) - I already have power source above - thanks
You would need the power cable, the NMEA 2000 cable, and the network cable.
The TZTouch doesn't have NMEA 0183, but if you need it can be pulled off your NMEA 2000 bus with a NMEA converter like the IF-NMEA2k2.
So does it appear I can mount it above with out issue? - before I start drilling just want to be certain it will work - not too worried about the vibration standard - (don't plan on running like coast guard
It has to do with maintaining a vibration and impact standard. We have seen many units mounted in the overhead without any problems. The concern is for very small boats that takes consistent hard impacts; then the mounting location wouldn't be recommended due to the extra vibration and physical impact the unit will experience.