# Running wire for well pump



## matkyne (Mar 8, 2012)

Just installed a well and need to run electrical power out to it. The run is about 100 ft, and the pump requires 240 and a 30 amp breaker. 

I plan to later install booster pump and maybe a light after I build the pump house. 

So here are my questions. 

First from what I can tell, I need 8 gauge wire. (right, wrong?)
and since I am running 240 volts, 3 wires (2 hot + a return). 

Since I might in the future need a 120V source out there do I need to run 4 conductor cable (8/3) or can I just split off a branch. 

Also I am confused about the cable I need. Does 240 need 3 wires or 4?

Also since underground cable is about 2x the price, I was planning on using PVC and installing regular cable. Thoughts?


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## rrolleston (Oct 17, 2011)

How long of a run total with the wire going down the well?


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## matkyne (Mar 8, 2012)

The well is about 900 feet deep. it is wire with 3 10 Gauge wires.


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## rrolleston (Oct 17, 2011)

If you are planning on running a booster pump and some 120v stuff out there maybe you could add a 50 amp sub panel out there with some 6-3 w ground wire and you would have power for both the pump, booster pump and some 120v outlets without running all separate lines. 6-3 wire panel couple ground rods and ground wire.

I have seen many people put a shed around the well. Having a dry place to do well maintenance and an option to run a winch to help pull the pump if you need to replace or repair the pump in the future would be well worth it.


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## Yoyizit (Jul 11, 2008)

So at 30A for a <5% voltage drop you need <.05 x 240v/30A = <0.4 ohm. For a 2000' loop distance you need a wire with <0.4/2000' = <0.2 ohms/1000'. 

#3 copper?


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## matkyne (Mar 8, 2012)

3 gauge wire seems excessive.


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## Yoyizit (Jul 11, 2008)

matkyne said:


> 3 gauge wire seems excessive.


To me, too.
Post your recommendation along with calcs.


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## Jim Port (Sep 21, 2007)

You cannot run indoor rated wire or cable inside a conduit that is outdoors or buried.

Straight 240 only requires 2 hot conductor and a ground.

If you are going to add other circuits you will need to run a feeder and add a subpanel. This would require a 4 wire feeder.


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## frenchelectrican (Apr 12, 2006)

matkyne said:


> Just installed a well and need to run electrical power out to it. The run is about 100 ft, and the pump requires 240 and a 30 amp breaker.
> 
> I plan to later install booster pump and maybe a light after I build the pump house.
> 
> ...





matkyne said:


> The well is about 900 feet deep. it is wire with 3 10 Gauge wires.




First thing first.,

The word 240 volt 30 amp for pump motour that means really nothing to me at all due we will need to know excat number like how many HP the motour itself that will make the differnce on sizing the conductor for the well motour.

Second thing the conductor size from your main panel to subpanel at the pump house if you want 40 amp circuit I can able tell you what size but need to know the distance from main panel to the pump house or at well head location is.

Third thing you can not run NM cable in conduit for underground useage it is not legal per NEC code so only way you can do this is use the Direct burial cable ( UF cable ) or run in PVC conduit with THHN/THWN conductors those two items are approved for underground runs.

Now next thing is sencie you mention light and couple other things so you will have to bring out 4 conductor not three conductor.

For the pressure switch will be at the well head or in the house that will make the differnce.

I know you mention 900 feet I have simauir depth well in Wisconsin but the pump itself is only down about 500 feet so I do not have to use seriously oversized conductor ( due I did have 480 volts triphase pump motour there ) 

Merci,
Marc


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## Yoyizit (Jul 11, 2008)

And maybe somebody makes a pump motor with a long driveshaft that hooks to a much deeper pump. Copper costs.


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## frenchelectrican (Apr 12, 2006)

Yoyizit said:


> And maybe somebody makes a pump motor with a long driveshaft that hooks to a much deeper pump. Copper costs.


Not for small well pumps. the larger one do have jackshaft set up so the motour stay at the top.

Merci,
Marc


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