Voltage Drop at well pump

[JoeNorm]

I am trying to size the conductors for a submersible well pump.

The pump is installed 600 feet deep with 8AWG run to it from ground level. Power from the transformer is 480 feet away and this where I am wondering how to size the wire. It will be direct burial URD.

The pump runs at 10-12 amps, likely with a startup of maybe 40 amps.

How should i approach the voltage drop calc with these kind of distances? I can get to the well house with 2-2-4 but then there is the 600' of #8 wire to consider.

Do you factor in the pumps startup amps or its running amps when doing the calc?

thanks for the help

 

[ptonsparky]

The submersible supplier usually has some recommendations for distance and related wire size.

Here, the well or pump installer is responsible for down hole VD. Size your underground for 2% VD @ FLA and report back your size.

This would have to be bare bones minimum install for me not put that in a raceway of some sort. No warranty past it working the first time.

 

[Dzboyce]

Joe

this is what ALL pump installers use to calculate wire size for submersible pumps

https://franklinwater.com/media/110562/M1311_60_Hz_AIM_12-14-WEB.pdf

The charts in the AIM manual have voltage loss calculations built into them

Do not, I repeat, DO NOT direct bury the wire. Put it in conduit.

is the pump installer pulling his own electrical permit? He is required to, and have a pump installers electrical license, EL03 or EL03A.

 

[Dzboyce]

Is it a 1.5 hp or a 2 hp motor? Could have used #10 wire if had of used a 3 phase motor with a VFD. The wire size savings would have paid for the VFD.

are you wiring to a pump house with a panel, 60 amp minimum size, or are you going direct to the well head?

 

[synchro]

Is it a 1.5 hp or a 2 hp motor? Could have used #10 wire if had of used a 3 phase motor with a VFD. The wire size savings would have paid for the VFD.

If a VFD is used on a submersible pump then the ramp should be kept relatively short to minimize wear on the pump's thrust bearing surfaces. When the pump shaft reaches a sufficient speed, then a film of water builds up between the surfaces of the hydrodynamic thrust bearing and it begins to support the axial load. But if the VFD ramp is slow then the bearing surfaces remain in contact longer and more wear occurs:

https://empoweringpumps.com/protecting-thrust-bearings-in-deepwell-submersible-pumps/

 

[junkhound]

If a VFD is used on a submersible pump then the ramp should be kept relatively short to minimize wear on the pump's thrust bearing surfaces. When the pump shaft reaches a sufficient speed, then a film of water builds up between the surfaces of the hydrodynamic thrust bearing and it begins to support the axial load. But if the VFD ramp is slow then the bearing surfaces remain in contact longer and more wear occurs:

https://empoweringpumps.com/protecting-thrust-bearings-in-deepwell-submersible-pumps/

Excellent practical advice!

 

[ptonsparky]

If a VFD is used on a submersible pump then the ramp should be kept relatively short to minimize wear on the pump's thrust bearing surfaces. When the pump shaft reaches a sufficient speed, then a film of water builds up between the surfaces of the hydrodynamic thrust bearing and it begins to support the axial load. But if the VFD ramp is slow then the bearing surfaces remain in contact longer and more wear occurs:

https://empoweringpumps.com/protecting-thrust-bearings-in-deepwell-submersible-pumps/

30 HZ within .5 second is what my goal was in the past. IDK if newer pumps are better now.