Wire size help needed

[Piggiron]

I've run into the most aggravating, want to beat someone around the head and shoulders, problem I've encountered in some time.
Not exactly shop related, but I'm trying to find info on wire size needed for a well pump.
The well for the new house is only 50' deep, but is located about 600' from the house.
Deep wells require larger wires due to the increased pump head and HP requirements, but linear runs do as well due to increased resistance.

What I'm looking at is a 1/2 or 3/4 HP submersible pump with approximately a combined 700' horizontal and vertical run.
The options I'm looking at are a 230v single phase pump or a constant pressure VFD 3 phase style pump, like a Grundfos, in the same HP range.
The question I'm trying to figure out is if the difference in required wire size for a constant pressure VFD 3 phase style pump will offset the increased cost of the pump vs a standard single phase. Given the length of the wire run needed, there's a big difference in the cost of 12 AWG vs 8 AWG wire, for example.

[Adasha_Machining]

That's an extremely long run of copper cable. Your voltage drop would be significant go the point that you'd wind up having to run #2 conductors.

This is what I would consider, because you're going to be into a cost no matter what, it's just a really long way...

Run #2 aluminum service cable, either direct burial or in conduit. And install a small weather rated 30A pony panel at the well head. Then run whatever (short) copper cable you want for either well pump size.

Around my neck of the woods, aluminum is used as service conductors, but cannot be used as branch circuits.
So as long as you install a pony panel, it would be allowed. Check your local codes. Or, don't and do it anyways.
The aluminum should be a great deal cheaper than copper.

[Piggiron]

Yes it is a long run. I was hoping for a shorter run, but hit rock at about 25' down and had to find new site for well.
As for local codes, I'm lucky in that being rural there are none.
I like copper over aluminum, but wouldn't rule it out. My current well, I was able to use 10 AWG using a 230v, 3/4 HP submersible pump. That well pump sits 70' down and about 300' run to the house.

Another possible option may be using a jet pump since the pump would be located at the house instead of the well, but maintaining pump prime can be an issue when using them.

One other consideration is, even though the well is 50' deep, the water level is up in the standpipe where it's capped 15' below ground level. Fill rate from the springs was around 17 gpm when initially dug. Most pumps, either jet or submersible, in the 1/2 to 3/4 HP range usually only put out a max flow of 10 gpm so if the make-up rate stays fairly constant, it will make up faster than it would be pumped out. The reserve capacity for the well liner is about 83 gals/ft so it would take running a lot of water demand to pull down the water level.

[chips and more]

1000 feet of 8awg is about $400-$500 x 3 OR 4. And you are lucky to have water at 50'. I had to go 400' down to find water. We all need water!

[chips and more]

What about a windmill? I suppose you would then need a holding tank and pump? But could be closer to the house.

[Piggiron]

And you are lucky to have water at 50'. I had to go 400' down to find water. We all need water!

Yep, a couple of the veins were only about 20' or so down. I don't have a good picture, but the red circled area on the attached Google Map screen capture is a ridge that runs WNW from the new house out to the road that apparently is a huge sandstone and limestone ridge about 10' to 15' under the soil.
The well (circled in Blue) hit right at the edge of the stone feature.
Here's a link to a couple short videos on my Google Drive of the well and well drill rig: https://drive.google.com/drive/folders

[Adasha_Machining]

It has nothing to do with liking one over the other - one is just better suited over the other vs price/cost.

Nearly all high voltage overhead cables are aluminum. All power plant service cables are aluminum. The feed to 90% of houses from the street is aluminum.
When you're going such a long way, just use aluminum service cables at a fraction of the cost over copper. It does not make any sense at all to use copper for a 700' run.
Also, the more you nip and tuck on wire gauge, the more the voltage drop, the more the pump is starved for current. You'll burn out more pumps.

I would never consider single phase 120v for any motor if 220v is available. Motors do not run well on 120v, period.

[Piggiron]

It has nothing to do with liking one over the other - one is just better suited over the other vs price/cost.

Nearly all high voltage overhead cables are aluminum. All power plant service cables are aluminum. The feed to 90% of houses from the street is aluminum.
When you're going such a long way, just use aluminum service cables at a fraction of the cost over copper. It does not make any sense at all to use copper for a 700' run.

I know, but I remember back in the 70's when mobile home manufacturers started using aluminum wires due to the copper shortage. There was a big rash of fires caused from it.
The issues were twofold. First, as loads were energize and de-energized, the wires were expanding and shrinking from the heat of resistance. This caused the connections at the breakers to compress more as it heated and became loose as it cooled. The heat also caused excessive corrosion at these points which flaked off further loosening the connection.
If they weren't frequently checked and re-tightened, the resultant arcs when the associated load was energized caught the insulation and other combustibles on fire.
After that, electric companies and insurance required only copper from the meter in even though it's aluminum on the supply side to the meter.

[Adasha_Machining]

Times have changed. Yes, aluminum is not allowed for branch circuits. But fine for service.
Use NoAlox (oxide preventer) at the connection point and torque the lug as per specifications written on the breaker or load center. These connections last for decades.

Or use copper at 5-6 times the cost?

That's my opinion.

But what is not opinion is the wire size over that distance. This is governed by code.

700' copper
120v 20a = 2/0 AWG
240v 20a = 3 AWG.

[Piggiron]

Good info Shawn. Now I have to find out what size wire would be required over that distance if I go with a Grundfos constant pressure pump.
Grundfos pumps are 3 phase variable speed pumps with controls that use PWM to convert single phase to 3 phase which, as I understand it, greatly reduces the needed wire size.
Then I can compare the difference in wire price to the difference in pump and controls price. The last difference being that the Grundfos constant pressure system uses a much smaller pressure tank.

[Adasha_Machining]

Is the plan to place the inverter at the pump or at the house?

What are the input ratings of the inverter and the input ratings of the motor.

Yes, converting to 3 phase decreases the current requirement per phase, but I would do some reading on how long the leads from the inverter to the motor can be. Voltage drop is voltage drop, doesn't matter what configuration it's in. I would be concerned about frequency loss and interference between the inverter and motor if the leads are of any significant length.

A quick Google search says leads from inverter to motor should be less than 150'.

[Piggiron]

As far as I know so far, Grundfos pumps are only sold through distributors/installers. Can't get one from a box store around here anyway.
The inverter control panel is mounted in the house along with the pressure tank, although this video shows it actually in the pump housing: https://www.youtube.com/watch?v=F-U5ORT6IFU

They make pump systems for everything from residential well pumps to huge ones for irrigation systems. I emailed them requesting info on local dealers/suppliers. I'll have to ask them about my specific situation and see what they say/recommend.

[Adasha_Machining]

What's the longest suction line anyone's ever experienced/heard of?
Keeping prime on 700' of pipe sounds problematic.
Altho, I guess if the pipe is solid and continuous, or well sealed/joined and doesn't crush, it would be a lot simpler, and cheaper, to have the pump at the house.
Is sold/rigid water pipe for a well something that can be done? Would the pump eventually collapse the pipe if it was the regular black pipe?

[Piggiron]

The horizontal run length doesn't really affect the pump, it's the vertical height that's the issue. I believe the maximum height a jet pump can draw water up from id 25'. While this might not be an issue given the current water height in my well, it would make to bottom 30' to 35' of water unusable. A situation I'd rather not have. Black plastic water pipe would work for this and allow for a single piece suction line from pump to well with the exception for the 90 degree turn at the well head.
Many, many, many years ago, I lived in a house that had a well with a jet pump. Instead of a foot valve, the owner had plumbed it using a discharge check valve. Pump seal and fitting leaks resulted in constant loss of prime issues. It was mounted on a platform in the well so every time it lost prime I had to climb down into the well and re-prime it. 
While a jet pump is a viable option that gets rid of the wiring concern, it causes other issues that I'd rather not deal with, if possible.

[Piggiron]

:UPDATE:
Seems my guesstimate was way off. I was able to borrow a measuring wheel today and measured in both directions from the center of the house (approx. location for load center) to the well head.
I got 513' one direction and 518' the other. Add in a fudge factor for bends, ups & downs, etc, and I'd say a max would be 550' with another 35' to 40' down the well.
Still a long run for wires, but better than the 700' guess just for horizontal length.