Well pump wiring help

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slc410

Electrician
Location
Madison wi
Occupation
Electrician
Trying to hook up an existing well pump to new wiring that the excavator ran underground into the house. The wiring termination in the outdoor pumphead doesnt seem right. The wires that come up from the well casing are black, red, yellow, and green. Which tells me i would need a control box in the house. But the excavator only ran a 12/2 w ground UF cable. Is there any legal way of making it work or do i need to make the call to have him run a 3 wire UF
 
slc410 said:
Trying to hook up an existing well pump to new wiring that the excavator ran underground into the house. The wiring termination in the outdoor pumphead doesnt seem right. The wires that come up from the well casing are black, red, yellow, and green. Which tells me i would need a control box in the house. But the excavator only ran a 12/2 w ground UF cable. Is there any legal way of making it work or do i need to make the call to have him run a 3 wire UF
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2 Choices.

1. Run a three conductor UF
2. Install a two wire pump
 
peter d said:
Most well companies here are doing away with the 3-wire feed now.
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Depends on what part of the country you are in. 2 wire pumps are more common in the north east and Midwest. About the only place you’ll find a 2 wire pump in the Pacific Northwest is in a big box store for the DIY crowd.

1 1/2 horsepower is the largest size you can get a 2 wire motor. Above that it’s going to be a 3 wire, single phase or 3 phase.

for the OP, about the only thing you can do besides replacing the wire or the pump, would be to move the control box to the well head. And that will be dependent on the horsepower of the pump motor.

incidenally, I NEVER install UF. All wiring to the well goes in conduit, and I pull Thhn, then splice to the submersible wire inside the well head.
 
Nearly all new domestic wells I have seen in recent years were VFD controllers and three phase pump motors.
 
kwired said:
Nearly all new domestic wells I have seen in recent years were VFD controllers and three phase pump motors.
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Probably 75% of the domestic pumps I install are 3 phase motors with a vfd controller converting the incoming single phase power to 3 phase output. On some deeper sets, the smaller wire size savings more than makes up for the additional cost of the vfd. I switched to the Pentair Intellidrive about 3 years ago and have not had a failure yet. The Intellidrive is a Danfoss drive customized specifaclly for submersible Pump applications. They had some teething pains with the 5 hp drive for a little while. I had 3 or 4 fail in the first 5 minutes, but they solved that problem quickly.
 
Dzboyce said:
Probably 75% of the domestic pumps I install are 3 phase motors with a vfd controller converting the incoming single phase power to 3 phase output. On some deeper sets, the smaller wire size savings more than makes up for the additional cost of the vfd. I switched to the Pentair Intellidrive about 3 years ago and have not had a failure yet. The Intellidrive is a Danfoss drive customized specifaclly for submersible Pump applications. They had some teething pains with the 5 hp drive for a little while. I had 3 or 4 fail in the first 5 minutes, but they solved that problem quickly.
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On deeper wells I am not seeing anything under 2 Hp either for pump motors. Three phase is more desirable for both current and length of run. Though these drives are capable of driving a typical single phase three wire motor three phase seems to be preferred.

I have an intellidrive on my single phase pump - but may consider three phase pump next time it needs replaced.
 
kwired said:
Nearly all new domestic wells I have seen in recent years were VFD controllers and three phase pump motors.
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ptonsparky said:
I let the pump installer put in a 3 phase pump/motor then took over from there with my own drive and control logic. Because I could. No PLC or HMI, yet.
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But the op only has two wires out to his pump.
 
rlundsrud said:
Wouldn't you have to use XHHN as it is a wet location?
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I don't think there is such a thing as XHHN, but you are on the right track, THWN or XHHW would be two most popular conductor types that would be rated for wet location.

Most of what we use anymore has multiple ratings THHN, TWHN, THWN-2 or XHHW, XHHW-2.
 
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