How to Check Continuity on a Three Wire Submersible Pump

October 27, 2022 Post a Comment

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wiring submersible pump - what wires are what ?
Author: donberry (TN) I messed up. Was getting new siding on my garage and I disconnected the wiring to my well. Contractor turned out to be really messed up and a few months later the siding is still not up and I fired the contractor. Wanting to hook my well back up since we are in the high 90's and my yard is screaming for water, it turns out I did not mark the wires as well as I should have as I did not think it would be months later when i was hooking it back up. The system is a submersible pump, a pressure tank with a pressure switch and a control box. I marked the wires going from the pressure switch to the control box and the fuse box, but did not mark the wires coming from the pump as it was lying outside. The problem - when they installed the submersible pump, they used 12 gauge wire but it is not color coded, so I have no idea what wire is what. Coming out of the pump are 3 wires but they are all the same color - is there anyway possible to determine what wire is what without pulling the pump. I am told the pump is submerged about 140 feet and I really hate to pull the pump to figure out what wire is what. I am taking for granted if I wire it wrong the pump will run backwaerds ? maybe shortening the life span ? ANY help is deeply appreciated.
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wiring submersible pump - what wires are what ?

Author: donberry (TN)

I messed up. Was getting new siding on my garage and I disconnected the wiring to my well. Contractor turned out to be really messed up and a few months later the siding is still not up and I fired the contractor. Wanting to hook my well back up since we are in the high 90's and my yard is screaming for water, it turns out I did not mark the wires as well as I should have as I did not think it would be months later when i was hooking it back up.
The system is a submersible pump, a pressure tank with a pressure switch and a control box. I marked the wires going from the pressure switch to the control box and the fuse box, but did not mark the wires coming from the pump as it was lying outside.
The problem - when they installed the submersible pump, they used 12 gauge wire but it is not color coded, so I have no idea what wire is what. Coming out of the pump are 3 wires but they are all the same color - is there anyway possible to determine what wire is what without pulling the pump. I am told the pump is submerged about 140 feet and I really hate to pull the pump to figure out what wire is what. I am taking for granted if I wire it wrong the pump will run backwaerds ? maybe shortening the life span ?
ANY help is deeply appreciated.

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Re: wiring submersible pump - what wires are what ?
Author: Fixitangel (NC) Use an ohmmeter, and check for continuity (low resistance) between the ground of the pressure switch and each pump wire. The ground wire from the pump will read low resistance to ground. The other 2 wires are the pump leads. Neither of the pump leads should read much continuity to ground, but will register a hundred ohms or so between each wire. That is the motor winding. The pump is AC so you cannot make it run backwards by reversing the leads. Likewise, you cannot hook it up so that it's lifefspan will be reduced. It will either work or trip a breaker. Turn the power off at the breaker before testing!! PS There's a chance that only 2 of the 3 wires are active, and the 3rd is not used (not grounded), depending on how the pump was wired on installation. I say all this, assuming you have a standard 240 volt pump and the usual SPDT type pressure switch. You mention a "control box".. is that a service disconnect or some other device? Edited 3 times.
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Re: wiring submersible pump - what wires are what ?

Author: Fixitangel (NC)

Use an ohmmeter, and check for continuity (low resistance) between the ground of the pressure switch and each pump wire. The ground wire from the pump will read low resistance to ground. The other 2 wires are the pump leads. Neither of the pump leads should read much continuity to ground, but will register a hundred ohms or so between each wire. That is the motor winding.
The pump is AC so you cannot make it run backwards by reversing the leads. Likewise, you cannot hook it up so that it's lifefspan will be reduced. It will either work or trip a breaker. Turn the power off at the breaker before testing!!

PS There's a chance that only 2 of the 3 wires are active, and the 3rd is not used (not grounded), depending on how the pump was wired on installation.

I say all this, assuming you have a standard 240 volt pump and the usual SPDT type pressure switch. You mention a "control box".. is that a service disconnect or some other device?

Edited 3 times.

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Re: wiring submersible pump - what wires are what ?
Author: North Carolina Plumber (NC) A control box is used with a 3 wire pump, the control box contains the starting capacitor. Usually its red + yellow for the 220 and black is your starting capacitor. Since you have no colors you'll need and ohm meter. The 2 wires with the lowest resistance will the for the 220, the remaning will be your start capacitor. As a side note I won't consider using a 3 wire pump with control box unless the pump is going to be deeper than 500', anything less than that I send the start capacitor down the well and use a 2 wire pump.
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Re: wiring submersible pump - what wires are what ?

Author: North Carolina Plumber (NC)

A control box is used with a 3 wire pump, the control box contains the starting capacitor. Usually its red + yellow for the 220 and black is your starting capacitor. Since you have no colors you'll need and ohm meter. The 2 wires with the lowest resistance will the for the 220, the remaning will be your start capacitor.
As a side note I won't consider using a 3 wire pump with control box unless the pump is going to be deeper than 500', anything less than that I send the start capacitor down the well and use a 2 wire pump.

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Re: wiring submersible pump - what wires are what ?
Author: hj (AZ) It is a single phase motor, so it will not run backwards, but a lot of other things could happen depending on how the motor has to be wired. A continuity tester MIGHT tell you which two leads are for the motor itself, but the third wire could be a ground or a capacitor feed. We cannot tell which without seeing a wiring diagram for the motor or the control box.
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Re: wiring submersible pump - what wires are what ?
Author: donberry (TN) 1st, thank u everyone for the replies. I am pretty proficient with a meter so I will get on that. It is a 3 wire 220v pump and I was thinking one wire (red) started the pump, one wire (black) kept the pump going and the 3rd is neutral ? so was not sure how the meter was going to tell me what was what- I am going to be digging deeper into it today (it is soooo hot here and we are the driest ion record here so my yard is begging for water) and will report back what I come up with. Thanks
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Re: wiring submersible pump - what wires are what ?

Author: donberry (TN)

1st, thank u everyone for the replies. I am pretty proficient with a meter so I will get on that. It is a 3 wire 220v pump and I was thinking one wire (red) started the pump, one wire (black) kept the pump going and the 3rd is neutral ? so was not sure how the meter was going to tell me what was what- I am going to be digging deeper into it today (it is soooo hot here and we are the driest ion record here so my yard is begging for water) and will report back what I come up with.
Thanks

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Re: wiring submersible pump - what wires are what ?
Author: hj (AZ) With plastic pipe, there is NO continuity between the control box ground and the pump's ground, so it will show "infinite" continuity.
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Re: wiring submersible pump - what wires are what ?
Author: Fixitangel (NC) Sorry if I misled you, as I have never seen a residential well with a control box. Most are simple single phase 240vac using W,B, and ground. If your control box motor terminals are marked Red Yellow Black then like HJ says one lead might be for a start winding or capacitor and if not connected correcly CAN cause troubles. You might check your wellhead. There may be a junction box there where the 3 black wires tie into the R-Y-B wires from the pump, and you can ID them. Here's a link to article that may be helpful: [ecmweb.com] Edited 1 times.
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Re: wiring submersible pump - what wires are what ?

Author: Fixitangel (NC)

Sorry if I misled you, as I have never seen a residential well with a control box. Most are simple single phase 240vac using W,B, and ground.

If your control box motor terminals are marked Red Yellow Black then like HJ says one lead might be for a start winding or capacitor and if not connected correcly CAN cause troubles.

You might check your wellhead. There may be a junction box there where the 3 black wires tie into the R-Y-B wires from the pump, and you can ID them.

Here's a link to article that may be helpful:
[ecmweb.com]

Edited 1 times.

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Re: wiring submersible pump - what wires are what ?
Author: LemonPlumber (FL) I would back to the relay box?we wire the box.we wire the pump based on the box?Just apump.easy.
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Re: wiring submersible pump - what wires are what ?
Author: Paul48 (CT) OK Elmer.
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Re: wiring submersible pump - what wires are what ?
Author: donberry (TN) okay, again thanks for all of the replies. I popped the lid on where the pump is and the wiring was spliced at the top and I could make out different colors on the wiring. There are 3 colors, Red, Green and Black. I took for granted the green was the yellow. I hooked them up to the control box and it sort of worked - the pump would kick on and start to fill the tank (is a 52 gallon tank I believe) but I turned on the faucet and it would run for only seconds then the pressure switch would immediately kick off. The gauge would go from say 30 psi to 0 instantly. Kept doing it so I pulled the gauge and switch to see if there was any think blocking the orifices as I do have sediment in the water. Did not help. The pressure switch is only a couple years old, but thinking it is a pressure switch problem now ? I am thinking I just need to get a new switch and gauge and see what I have. I did try to "drain" the pressure tank to clean it out some - it is also only a couple of years old. It had a small tank on it and I was hoping to be able to water my lawn so bought this one. Turned out I have so much sediment in my water it kept clogging the sprinklers. I bought a filter, but I think the pump is too low because it would clog up after a few days too. Looks like I will be doing some well work after all.......is our driest year on record and using city water to water my lawn is costing me a small fortune........
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Re: wiring submersible pump - what wires are what ?

Author: donberry (TN)

okay, again thanks for all of the replies.
I popped the lid on where the pump is and the wiring was spliced at the top and I could make out different colors on the wiring. There are 3 colors, Red, Green and Black. I took for granted the green was the yellow. I hooked them up to the control box and it sort of worked - the pump would kick on and start to fill the tank (is a 52 gallon tank I believe) but I turned on the faucet and it would run for only seconds then the pressure switch would immediately kick off. The gauge would go from say 30 psi to 0 instantly.
Kept doing it so I pulled the gauge and switch to see if there was any think blocking the orifices as I do have sediment in the water. Did not help.

The pressure switch is only a couple years old, but thinking it is a pressure switch problem now ? I am thinking I just need to get a new switch and gauge and see what I have.

I did try to "drain" the pressure tank to clean it out some - it is also only a couple of years old. It had a small tank on it and I was hoping to be able to water my lawn so bought this one. Turned out I have so much sediment in my water it kept clogging the sprinklers.
I bought a filter, but I think the pump is too low because it would clog up after a few days too.
Looks like I will be doing some well work after all.......is our driest year on record and using city water to water my lawn is costing me a small fortune........

Post Reply

Re: wiring submersible pump - what wires are what ?
Author: hj (AZ) IT would be a "rare" wiring system that used a green wire for anything other than a ground, unless the yellow wire, not the green one, came FROM the pump.
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Re: wiring submersible pump - what wires are what ?
Author: mr leak (CA) Although a submersible water pump may not be attached to the metal well casing, the code requires that the casing be bonded to the cfircuit equipment conductor.
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Re: wiring submersible pump - what wires are what ?
Author: LemonPlumber (FL) Black white and g.or g plus g striped plus?red to black phase
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Re: wiring submersible pump - what wires are what ?
Author: hj (AZ) Do not give electrical advice. You will get someone electrocuted.
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Re: wiring submersible pump - what wires are what ?
Author: LemonPlumber (FL) Only you hj.never a color has fired a ground. Naturals/neutrals.?I am not sure he even knows the number of phases of his pump?
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Re: wiring submersible pump - what wires are what ?
Author: norm (PA) Hello I have a sumo Submersible Pump made in England, it was in the well when we bought our house. I would like to get it running again. It also has red, black, green wire. the pump has no control box and the water line was cut off. green wire seems like the cap, the red is the run and the black is the start? I had it running in that manner. If i changed the red and the black the water flow was not as much. but I'm not even sure of what cap or caps i need. I'm trying the pump with a 40uf cap for now. It will start as soon as i take the cap out of line it slows down, not sure if it's even getting up to speed? sumo pump mod 12b1 hp.33 no. g79495 volts 220 rpm 3400 con 20 ~ 60 gph 280/500 head 160/90 ft stages 12 mg 4312 Hope someone can help!! Thanks Norm
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Re: wiring submersible pump - what wires are what ?

Author: norm (PA)

Hello
I have a sumo Submersible Pump made in England, it was in the well when we bought our house. I would like to get it running again. It also has red, black, green wire. the pump has no control box and the water line was cut off. green wire seems like the cap, the red is the run and the black is the start? I had it running in that manner. If i changed the red and the black the water flow was not as much. but I'm not even sure of what cap or caps i need. I'm trying the pump with a 40uf cap for now. It will start as soon as i take the cap out of line it slows down, not sure if it's even getting up to speed?

sumo pump
mod 12b1
hp.33
no. g79495
volts 220
rpm 3400
con 20
~ 60
gph 280/500
head 160/90 ft
stages 12
mg 4312

Hope someone can help!!
Thanks Norm

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How to Check Continuity on a Three Wire Submersible Pump

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