Wiring for Auto Pilot and GPS

[Joe_A]

Hi
I want to add an Auto pilot and GPS . The Auto pilot is Wheel driven and The GPS
will be rail mounted on the helm.  Just not sure how to run or where to get the power from ?
Should I do a homerun right from the breaker panel or is there some where else I can pickup the feed.
I would think the GPS and Auto pilot ... could be on the same feed ??

[Jon Schneider]

There are many more who know much more about electrical theory than I, so take my comments on the use of Mr. Franklin's invention with a heavy dose of salt.  I would not run both appliances on the same circuit, especially not a shared circuit with something else.  If your current wiring is OEM, it's not very robust.  My distribution panel has a specific autopilot circuit breaker.  If yours doesn't have that, I would use a spare or install a new one dedicated to the autopilot.  The wheel pilots aren't too bad in power consumption, but they're bad enough, and it's certainly quite possible that the AP will get stuck, jammed, or freeze, and suck a fair amount of juice through a fragile, probably under-gauged wire.  I would use 10 AWG wire, but check with the manufacturer's recommendation based on the length of the run (probably about 20'-25').  If the manufacturer's instructions are vague on this point, Blue Sea Systems has some good information (and a tool) to help you determine wire gauge and protection. 

That said, you should have no problem ganging the GPS onto the Nav/Comm circuit breaker.  Again, run a discrete line.  This one can be smaller, but I'd hesitate to venture a guess.  Personally, I over-gauge everything, so I would instinctively use 14 AWG in this case (along with appropriate data cabling), but there are wire bundles specifically meant for GPS/data service.  My favorite "wire store" is: bestboatwire.com.  You can find the wire bundles I'm describing there, as I'm sure you can at WM, Defender, etc.  They45 sell good quality "Level III" copper wiring (same as Anchor, but I don't believe that they actually sell Anchor, which is considered one of the better marine wire brands.  (I have no financial interest in any of these companies.)

[Ron Hill]

Joe : If you want a precise answer then let us know your hull# and production year!! 
Please Update your profile!

You already have 12v coming from the main nav station to the engine instrument panel that is switched by the battery selector (ON/OFF/1/2).  It's an easy matter to tap into that 12v at the key switch and hard wire it to the auto pilot with an in-line fuse. 
For the GPS you could do as I just did and use a cigarette lighter plug.  I made a temporary mount for my new Garmin chart plotter.  Found that the temp mount (vrs hard perminant mount) was sooo much nicer that I'm going to leave it that way!  Don't forget that in-line fuse.       

[Steve S.]

Just did this, Joe.  Others are right, run two power lines. one to the autopilot, the other to the GPS.  If you are mounting an S1 pilot, you don't run the power to the display head, you run that to the computer somewhere else on the boat.  (I put mine in the aft locker, in the aft saloon).  So, if you are going to mount your GPS on the helm (binnacle), you would have to run a separate power line anyway.