Resi well Voltage drop

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electricmanscott

electricmanscott

Senior Member
Location
Boston, MA
I have to power a well at a house. The well is 170' from the house and 500' deep. The well contractor has #12 in the well casing. My concern is voltage drop. It is not something I am very familiar with. I am looking for thoughts on what this should be fed with.
 
Re: Resi well Voltage drop

I went to electrician.com and used their VD calulator. Its very instructive. Assuming 240V.

Load(A) VD(Volts)
20 52.9
15 39.7
10 26.5
5 13.2
 
Re: Resi well Voltage drop

I didn't know that wells used electricity. I thought they were just holes in the ground. :(

[ December 13, 2004, 06:16 PM: Message edited by: charlie b ]
 
Re: Resi well Voltage drop

A 500' well!! Yikes!! :D

I don't know if pump cable is available in large sizes but I will check. It seems like the well hacks (as it relates to the wiring they do) around here only run #12 anyway...same old story. :roll: :mad:

I hope this helps.

[ December 13, 2004, 06:25 PM: Message edited by: peter d ]
 
Re: Resi well Voltage drop

I believe that just because the well is drilled 500' deep, the pump itself may not be located at that depth. Generally it is suspended at a level which that water rises to.The depth of the well is needed to reach the aquifer in which desirable water is located. This may not be the case with your installation, but I have seen this setup before. For what its worth!
 
Re: Resi well Voltage drop

I found out today it is a 3/4 horsepower pump at 240 volts. the pump is down at 400 feet. The run to the house is 170 feet. I'll try the online calculator.
 
Re: Resi well Voltage drop

This is what I figured out: #10 for the submersible cable down the well, and #8 to feed out to the well head.
 
Re: Resi well Voltage drop

Scott, Need to know HP and how many stages for GPM output. (Assuming 240 V,1 PH.)Setting the deep submersible is easy, pulling it out from 400' is another story. How far down is the casing...Just curious.

rbj, Seattle

[ December 18, 2004, 09:59 AM: Message edited by: gndrod ]
 
Re: Resi well Voltage drop

peter d,

I did read your posts and 10 AWG minimum with an #8 feed is correct. The static head you mention is another factor if the impeller sections do not match the GPM output requirements. With that said, a 3/4 horse may not be adequate. I think the main issue is getting the pump up or down the well. (usually 6" casing)

Sometimes the driller needs to case beyond the required minimum depths because of geological fissure anomalies. I've been on jobs where casing to 400 ft was necessary due to cave-ins.

electricmanscott, I'll re-phrase my question with additional info you may be interested in.
What is the driller's Gallon per Minute final report and what is the well output design intention? With that data a better answer would be forthcoming. Also note, rural insurance firms usually require a minimum output in case of long fire response time to the site. In some cases I have installed storage tanks to compensate for low yield wells. Yes, another high output pump is generally needed.

rbj, Seattle

[ December 23, 2004, 07:45 AM: Message edited by: gndrod ]
 
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