what size electric wire(gauge) should i use for a 400' run for a water pump that pulls 16 amps 220 service

Answer 1

How about some real numbers?

#10, at 1 ohm/1000' ---0.8ohms, 12.8V drop, 205W
#8, at 0.628 ohms/1000' ---0.5 ohms, 8V drop, 128W
#6, at 0.395 ohms/1000' --- 0.3 ohms, 5V drop, 80W

The #10 is really a bit light as it will drop over 5% of the voltage. I'd go with #8, unless I wanted the absolute max pressure from the pump, especially if there's an uphill climb, in which case I'd go with the #6.

BTW, even tho I included the wattage burned in the wire, you won't really save electricity with a heavier gauge - you'll just run more efficiently, since you'll get more horsepower out of the pump for the same total wattage.

Answer 2

This will not be the best answer. I believe you have two questions here. You have a 3/4 hp motor that will draw 13Amp on 115 volts at 60 Hearts or Cycles and that can be also wired by changing the way it is hooked up to draw 6.5 Amps at 230 volts on 60 Cycles. Other Question is about wire size concerning voltage drop over 500 feet of distance. Check out Ohm's law Though it should not be used for general a.c. motor and transformer circuits or a circuit containing any e.m.f or voltage other than the impressed voltage. (re all ref. - Practical Fundamental of Electricity.) One mile of copper wire a Quarter of and inch diameter offers about 1 ohm resistance. . You need to also question how many wires you need to run in your cable; whether it is one white one black and one green safety ground or all the former and a red besides . Be aware that the smaller the number of the wire, the larger the size of the wire; that a number six wire is much thicker than a number 16 and that the former offers less resistance. Getting an electrician to put all of these facts together and hook up your water pump will keep you in good stead with your insurance company even if you know how to do the job yourself as well as keep you from burning out your motor.

Answer 3

I'd use #6 wire for such a long distance. Check the NEC manuals for loss per hundred feet of wire for what you need, for the best answer.
While #10 would carry the load, the loss due to copper resistance would over come it's capability to carry the load at 400 ft. That is why I recommend #6, although, #4 might be a better choice.

Answer 4

10 gauge would be sufficient, but 8 gauge would give you less line-loss, so the pump would run cooler and more efficiently.

.

Answer 5

10 gauge sounds about right.

http://www.powerstream.com/Wire_Size.htm