As of late I've had several new build jobs that are in rural areas without city water. Some of the well drillers provide 3 wire( 2 power& equip ground) .75hp 230v single phase pumps which just tie into the bladder tank pressure switch.Others provide .75hp pumps but utilize 4 wire and a Franklin or Gould controller with capacitor/relay etc. Is one way better than the other? The answer I get from the well guys is this is what we always used. Thanks.
3 wire vs 4wire well pump
- Thread starter nizak
- Start date
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junkhound
Senior Member
- Location
- Renton, WA
- Occupation
- EE, power electronics specialty
my own pumps are controller with capacitor/relay and 2x overrated contactors
Cap or relay fails, ya don't have to pull the well string. Using contactors at rating have a bad habit of welding closed after a few years of operation, oversizing reduces the risk of running continuously which is of more consequence for a well pump than most above ground applications
Cap or relay fails, ya don't have to pull the well string. Using contactors at rating have a bad habit of welding closed after a few years of operation, oversizing reduces the risk of running continuously which is of more consequence for a well pump than most above ground applications
The two wire set up has the controls and the capacitor builtin and it goes down the well with the motor vs three wire system has the controller and the capacitor outside of the well on a post or a wall.
IMO servicing electrical devices and equipment outside of the well is much easier and less costly to the customer.
IMO servicing electrical devices and equipment outside of the well is much easier and less costly to the customer.
- Occupation
- Licensed Electrician
Well guys here are the same. They use one or the other but just because that is what they always have done.
Having the cap and switch above ground makes sense but may not matter so much based on my experience. We get one person a month at least bringing in a capacitor because their well is not pumping. Almost always the cap tests good. Relays are usually ok too, but nobody wants to pull the pump so they go ahead and change the parts that are easy, hoping it will make things work, and end up pulling the pump anyway.
So I have concluded the best thing to do is get a good well guy (they are as easy to find as a clean shaven biker) and let him install what he likes.
Having the cap and switch above ground makes sense but may not matter so much based on my experience. We get one person a month at least bringing in a capacitor because their well is not pumping. Almost always the cap tests good. Relays are usually ok too, but nobody wants to pull the pump so they go ahead and change the parts that are easy, hoping it will make things work, and end up pulling the pump anyway.
So I have concluded the best thing to do is get a good well guy (they are as easy to find as a clean shaven biker) and let him install what he likes.
Barbqranch
Senior Member
- Location
- Arcata, CA
- Occupation
- Plant maintenance electrician Semi-retired
I have a 3 wire pump (1 hp) in the well at my house. I have had a controller go out (after 10 years and millions of gallons) as well as a pump go out (at another time). One advantage of a 2 wire unit is less wire (can easily be several hundred feet). One advantage of the 3 wire unit is there is less voltage drop on start-up, since starting current is spread between all 3 wires.
The 3 wire control plugs into the base, and so after it went out, I took the male and female connectors and made a breakout cable in order to better trouble shoot it if (when) I have trouble in the future.
The 3 wire control plugs into the base, and so after it went out, I took the male and female connectors and made a breakout cable in order to better trouble shoot it if (when) I have trouble in the future.
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