600 yard to pump

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winnie said:
@James L makes a good point about calculating the actual cost of energy loss in the wires.

My point about voltage drop during starting is about performance. If you have too much voltage drop then you can have issues with starting up the pump.

-Jon
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Submersible pumps seem to have a high tolerance for low voltage, I’ve seen some operate for years on really long runs, where the well installers ran #10, not even counting the length down the well! Around here, the well people always runs the wire, and we just connect to the pressure switch.
 
Also, I doubt the pump actually draws 12A - that is what the NEC chart says....

I agree with hillbilly, I wouldn't be too anal with the voltage drop. I wouldn't have a problem with 10% drop if there is big money to be saved and hassle to be avoided.
 
This all sounds "Scary" to me ... Easements, going under roadways, and another's property. The big one for me is "Direct Burial", I don't feel comfortable at all with this scenario. Why would you have a well pump so far away ? Please educate me.
 
he wants to keep his current pump since it’s brand new.

I looking to run 6 xhhw alum . Getting a buck boos transformer and boasting to around 280volt with around 13-18% vd I’ll end up with around 240 at end.
Total cost of the 6 xhhw is around 2.4k have not looked into the transformer cost.
Seems like a better option than upsizing wire with the 242 at source I have.
Is that a dumb idea?

We did a quick google earth measurements at its 630 meters
 
electrofelon said:
Also, I doubt the pump actually draws 12A - that is what the NEC chart says....

I agree with hillbilly, I wouldn't be too anal with the voltage drop. I wouldn't have a problem with 10% drop if there is big money to be saved and hassle to be avoided.
Click to expand...
I get your point but inspectors going to ask that and I don’t want to deal with him.
 
If you're directional drilling to get new electrical conduit in the ground, now is the time to put new pipe in the ground for the water back to the house. I'd be tempted to have the drilling co. put something like a 3" HDPE conduit in the ground, and then pull a new water line and direct-burial rated tray cable through for power. Easy to replace either if/when they have a problem. Definitely cheaper than paying to excavate/drill again.

www.wireandcableyourway.com

#4-3C THHN-PVC Tray Cable, No Ground

THHN-PVC Tray Cable without Ground. Cut to length - sold by the Foot.
www.wireandcableyourway.com www.wireandcableyourway.com


SceneryDriver
 
Interesting point on the boost transformer.

Generally it is a bad idea to use a boost transformer for voltage drop, because when the load changes the voltage will be excessive during low load conditions.

But in this case there is only one load, and a control switch. Either the motor is operating and you have voltage drop, or the power is off and you don't have any voltage at all.

Would you put the switch downstream of the boost transformer (transformer is always energized, switch has to deal with boosted voltage) or would you put the switch upstream of the boost transformer (switch has to deal with transformer inrush current).

I guess the transformer would be pretty small, say a 240V:24V 0.5kVA transformer wired in boost configuration to compensate for a 10% voltage drop. I would still be concerned about voltage drop during starting.

-Jon
 
currently the only thing turning the pump on and off is a Pressure switch to my knowledge I will be walking the site tomorrow to get a better look.
If I have to use a pump control then I was thinking I would put transformer before the switch. I don't think the parts on that would be that sensitive to the voltage increase. Though I have not ever really taken a hard look at the components ratings in them.

More I think though at the pump motor may be better. The transformer inrush would be a short spurt vs the long exposure I was originally thinking.
 
SceneryDriver said:
If you're directional drilling to get new electrical conduit in the ground, now is the time to put new pipe in the ground for the water back to the house. I'd be tempted to have the drilling co. put something like a 3" HDPE conduit in the ground, and then pull a new water line and direct-burial rated tray cable through for power. Easy to replace either if/when they have a problem. Definitely cheaper than paying to excavate/drill again.

www.wireandcableyourway.com

#4-3C THHN-PVC Tray Cable, No Ground

THHN-PVC Tray Cable without Ground. Cut to length - sold by the Foot.
www.wireandcableyourway.com www.wireandcableyourway.com


SceneryDriver
Click to expand...
I like the cable never have used that before. Though price would be 4k more than using xxhw .
My next issue is now how am I going to pull this 2k feet lol. Over size the pipe and lube the crap out of it. Its going down hill so should slide fine ( I think).
I never dealt with Bouring conduit is it easy to pull like PVC or is it like LFNC as far as difficulty.
 
AC\DC said:
I like the cable never have used that before. Though price would be 4k more than using xxhw .
My next issue is now how am I going to pull this 2k feet lol. Over size the pipe and lube the crap out of it. Its going down hill so should slide fine ( I think).
I never dealt with Bouring conduit is it easy to pull like PVC or is it like LFNC as far as difficulty.
Click to expand...
HDPE pipe is very smooth inside. I'd call this a sleeve though - it doesn't have to be "conduit" as you're using it to sleeve a direct-bury rated cable (and a water line as well). I've never pulled 2kft though it's done all the time. Lots of lube would be your friend.


SceneryDriver
 
AC\DC said:
he wants to keep his current pump since it’s brand new.

I looking to run 6 xhhw alum . Getting a buck boos transformer and boasting to around 280volt with around 13-18% vd I’ll end up with around 240 at end.
Total cost of the 6 xhhw is around 2.4k have not looked into the transformer cost.
Seems like a better option than upsizing wire with the 242 at source I have.
Is that a dumb idea?
Click to expand...
Typical.
You electrician need to be "creative" at an excessive cost of lack of performance, simply because I don't want to spend money replacing the stuff I own that is wrong.
 
With an 1800 foot run, the difference in cost of wire (different pumps with different requirements leading to different wire types) could exceed the cost of replacing the pump.
 
ptonsparky said:
Why replace the pump? So you can use 480? Do they make 480 volt single phase pumps? No? That means a conversion to three phase. Static, rotary or VFD. $s keep adding up.
Click to expand...

It is all numbers.

If you go to a 480V three phase pump, and add a voltage doubling VFD, then you are paying more for the pump and controller. (much more when you consider that the existing pump is already paid for and thus 'free').

But a 480V three phase pump means far smaller/cheaper wire. At 1800 feet that difference could pay for the new pump.

It is stupid to throw $2000 at a pump and controller to save $500 in wire. But it is equally stupid to throw an extra $2000 in wire to save a $1600 pump.

As someone else stated: there are going to be lots of ways to skin this cat. Lots of trade-offs, eg. allowing higher voltage drop to save on wire costs.

I personally would not design for more than 10% voltage drop running, even with a boost transformer helping out. But I would certainly compare the wire cost vs cost of electricity 'lost' by having a high voltage drop. Using 6 AWG Al for this single phase pump is IMHO borderline, but probably good enough. And loads cheaper than the wire originally being discussed.

(Side note: voltage drop calculations often use the resistance of wire at 75C. But wire used for a long run is oversized vs ampacity, and will run cool. The resistance used for voltage drop should probably be about 20% lower, meaning that if the calculator says you get 10% drop, you probably only have 8% drop.)
 
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