I need to run an electrical line from my barn to the pond.
Will tie in to my fishing pier...  plan to run  (at most) a mini-fridge, ceiling fan, a couple of 100 watt light bulbs and.... a 10 amp pump for the pond aeration system.

Length of run will be 450 feet from barn to pier. Will encase wire in conduit and bury 18".

What type/gauge wire will I need?

Thanks!

Buy a small 6-8 circiut 60 amp or 100 nema 3R panel(30-40 bucks) run 6/3with ground and you will be good to go.Put the lights,fridge,pump on breakers in the sun panel.

Add up the total watts on your circuit. Nameplate of frig and pump should have it. Divide by voltage of circuit. (ex; 120v, or 125v,...)
Watts/volts=Amps
Then go to this handy calculator.

http://www.elec-toolbox.com/calculators/voltdrop.htm

I would recommend compact screw-in flourescent lamps; plenty light with low watt draw. Will probably attract less bugs on the dock, too.

Stay safe.

Quoted: Add up the total watts on your circuit. Nameplate of frig and pump should have it. Divide by voltage of circuit. (ex; 120v, or 125v,...) Watts/volts=Amps Then go to this handy calculator. http://www.elec-toolbox.com/calculators/voltdrop.htm I would recommend compact screw-in flourescent lamps; plenty light with low watt draw. Will probably attract less bugs on the dock, too. Stay safe.

What my constiuent said, and with much more brevity than I would have.

What he did not mention that I will is that it is always better to oversize any load for future considerations.  So, if you find your minimum size wire is a #6 copper AWG, I would install nothing less than #4, and probably #2.  You never want to have to pull new feeders because you added stuff to the circuit in the future, such as a 500-watt Metal Hallide outdoor lamp to light the dock.  You also need to consider non-connected loads, such as a vacuum cleaner, the margarita blender, or other high-draw appliances that will put a serious drain on a taxed system.  

A little more now can save you a lot later.  I make a lot of money re-doing things because a homeowner tells me, "Well, I never really thought I'd actually buy that welder, and this wire was cheaper than that wire, and it's all I needed at the time, so..."  Then I end up replacing the feeders, sub-panel, and etc.  Costs them twice as much more than simply paying a little more for what they didn't really then, but do need or would like to have now.  Many times, it's just not thinking ahead for thigs as mentioned above, or a bench grinder, or some similiar device that dims their lights or trips the breaker every time they hit the on the switch and the spike amperes kick in.