Wiring a Well Pump

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  #1  
Old 10-08-09, 10:59 AM
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Wiring a Well Pump

Want to power 1hp,230v submersible well pump from a 100 amp panel 60 ft away (75 ft of cable). The well is 80 ft deep and currently has 12 ga wire from the motor to a plug at the well head.

Conduit: I've installed 1" gray sched 40 PVC from the panel to the future pump house. It's 24" deep and bedded in sand.

Wire: Will 3-wire (2 hots, 1 neutral, 1 ground) 12 ga UF cable inside the conduit work ? Is there a special pump control box I need to put inside the pumphouse?

Breaker: What size breaker should I use at the main panel?
Should I use a shutoff switch at the pump house?

Ground: Any need for additional grounding beyond the ground rod for the main panel?

Dave
 
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Old 10-08-09, 11:24 AM
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Wire: Will 3-wire (2 hots, 1 neutral, 1 ground) 12 ga UF cable inside the conduit work ? Is there a special pump control box I need to put inside the pumphouse?
No neutral needed for a 240v pump but I would suggest pulling the 4 THWN wires any way. That way you can put in a small 30a subpanel and have 120v available for lights and a receptacle. A 30 amp breaker at the main panel and 2 black #10, a white #10 and a green #10 should do. If you use a subpanel you will ned one or two ground rods at the pump house. You could probably use a 15a 2pole breaker in the subpanel and a #14 whip for the pump. If the subpanel pump breaker is in sight of the pump it will serve as disconnect.
 
  #3  
Old 10-08-09, 11:27 AM
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Originally Posted by Stoney Point View Post
Wire: Will 3-wire (2 hots, 1 neutral, 1 ground) 12 ga UF cable inside the conduit work ?
The neutral wire is not required; only two hots and a ground. You don't need UF-B cable in the conduit. Use THWN individual conductors pulled into the conduit in colors black, red and green.

Is there a special pump control box I need to put inside the pumphouse?
Generally no, unless the pump manufacturer requires one.

What size breaker should I use at the main panel?
Generally 15A double-pole breaker for a 1HP pump, but follow the pump manufacturer's directions if they are different.

Should I use a shutoff switch at the pump house?
Yes. A simple $10 air conditioner disconnect is sufficient.

Ground: Any need for additional grounding beyond the ground rod for the main panel?
No.
 
  #4  
Old 10-08-09, 03:47 PM
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Want to power 1hp,230v submersible well pump from a 100 amp panel 60 ft away (75 ft of cable). The well is 80 ft deep and currently has 12 ga wire from the motor to a plug at the well head.
How may wires at this plug....3 or 4 ? ...include the ground.

3 wire with ground well pumps require a control box.

If pump wire was used a 2 wire with ground pump will have black and red wire

If 3 wire with ground then the wire colors will be black,yellow and red.
 
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Old 10-09-09, 12:37 PM
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Spent couple hours pumping rain water out of the pumphouse excavation..but did verify

Bruto, The existing plug is a 2-wire with ground (red, black, green). Therefore, no need for a control box? And Ray's suggestiong for a subpanel would work?

Ray, Is the 14ga whip tha wiring for the 110v circuit coming out of the subpanel?

If I use a subpanel, then is there any ground wire connected back to the main panel 60 ft away in a separate building?

If I use an A/C disconnect, then no ground rod needed at pumphouse?

Dave
 
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Old 10-09-09, 12:51 PM
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Originally Posted by Stoney Point View Post
Bruto, The existing plug is a 2-wire with ground (red, black, green). Therefore, no need for a control box? And Ray's suggestiong for a subpanel would work?
No control box needed. If you only want to power this pump then no subpanel is required. If you want to power anything else at the pumphouse like a general-purpose receptacle or lighting then a subpanel would be required.

Ray, Is the 14ga whip tha wiring for the 110v circuit coming out of the subpanel?
No, the pump can be wired with #14. I recommended the #12 to compensate for the distance to the pump house.

If I use a subpanel, then is there any ground wire connected back to the main panel 60 ft away in a separate building?
Yes. If you install a subpanel, then two hots, a neutral and a ground are required. You would also need a grounding electrode which can be copper rods or the well pipe/casing itself if it is metal.

If I use an A/C disconnect, then no ground rod needed at pumphouse?
A grounding electrode is only required if you use a subpanel. You also said the pump has a plug. If that is the case then no additional disconnect is required as the plug and receptacle is considered a legal means of disconnect.
 
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Old 10-09-09, 09:26 PM
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Thanks to all for inputs. I propose to do the following...

1. Install 2 pole 20amp breaker at main panel.
2. Run 3 wire 12 ga w/ground to subpanel at pumphouse.
a. At main panel connect the two hots to the breaker, the neutral and ground to the neutral/ground bus bars.
b. At the subpanel do not connect the ground to same bus as neutral. Use separate bus. This from Bruto's Sticky Note line diagrams which are very helpful.

At Pumphouse

3. Install 15 amp breaker in subpanel for 110v light/GFI outlet circuit using 12 or 14 ga in conduit. Outlet would be used to power pressure switch for pressure tank located in the pumphouse.
4. Install 2 pole 20 amp breaker and run 12 ga wire (two hots and ground) in conduit to 220v outlet for existing well pump plug.
5. Run #6 copper from subpanel ground bar to 8 ft grounding electrode next to or under the pumphouse. Well casing is PVC.

Is this plan workable?
 
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Old 10-09-09, 09:37 PM
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Originally Posted by Stoney Point View Post
b. At the subpanel connect same as a. above.
This is different at the subpanel. You need to buy an add-on ground bar kit for the sub and remove the neutral bonding screw or strap from the neutral bar. Neutrals and grounds must be kept separate at the sub.
 
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Old 10-09-09, 09:44 PM
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Duly noted, IP. I just finished editing my previous post after reviewing Bruto's Subpanel Sticky and found your input. So I take it the rest of the plan is sensible? Dave
 
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Old 10-10-09, 08:30 AM
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In your first post you wrote: I've installed 1" gray sched 40 PVC from the panel to the future pump house. It's 24" deep and bedded in sand. If you have that no need to use cable. Just pull THWN individual conductors or is that what you meant by:
Run 3 wire 12 ga w/ground to subpanel at pumphouse.
 
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Old 10-10-09, 08:34 AM
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Stoney Point Proposed:
4. Install 2 pole 20 amp breaker and run 12 ga wire (two hots and ground) in conduit to 220v outlet for existing well pump plug.
As ibpooks wrote:
Generally 15A double-pole breaker for a 1HP pump, but follow the pump manufacturer's directions if they are different.

...................
 
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Old 10-10-09, 05:11 PM
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Ray, I have 12 ga Underground Feeder (UF) cable handy so thought I'd just use it. It would take up a bit more space in the 1" conduit, but I'm reconsidering just using THWN wire.

15A vs 20A double-pole breaker at the pump house...will verify if 20A is required as soon as I find the pump motor documents.

Here's an additional question: Can one easily find a small subpanel with 4 spaces, i.e., 2 spaces for the double-pole breaker, 1 for the 110V lighting/outlet circuit and 1 spare??
 
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Old 10-10-09, 05:31 PM
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Originally Posted by Stoney Point View Post
Ray, I have 12 ga Underground Feeder (UF) cable handy so thought I'd just use it. It would take up a bit more space in the 1" conduit, but I'm reconsidering just using THWN wire.

15A vs 20A double-pole breaker at the pump house...will verify if 20A is required as soon as I find the pump motor documents.

Here's an additional question: Can one easily find a small subpanel with 4 spaces, i.e., 2 spaces for the double-pole breaker, 1 for the 110V lighting/outlet circuit and 1 spare??

Let me step in here for a minute the UF in the conduit normally not allowed but for a short section it is allowed only for protection from damage.

However if you have conduit run all the way from the main panel to subpanel at the pump house then you have to run the THHN/THWN conductors.

For 1 HP motor if that draw on 8 amps on 240 volts you can use the 15 amp breaker without any issue however if hard starting you can go 20 amp but becarefull with conductor distance the voltage drop will affect the motor performace so stick with #12's that is good up about 150 feet total run if more than that you have to upsize it to comperised the voltage drop.

Speaking of small subpanel yes there is few diffrent verison on market and you can able find them in big box store without any issue at all they have in two , four and six space verison. { you can find two and six space pretty easy but four space verison it will be depending on the box size }

If you going to use the subpanel at the pump house and the pressure switch is at the pump house you are fine with that set up but if the pressure switch is at the house then you have to keep it seperated from the pump house genral circuits so that something you have to keep in your mind.

A simple A/C pull out switch will meet the code if the pressure switch is at the house { I useally use the double pole switch and set at the diffrent location so you can not get this mixed up at all }

Merci,Marc
 
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Old 10-12-09, 09:58 PM
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Originally Posted by french277V View Post
For 1 HP motor if that draw on 8 amps on 240 volts you can use the 15 amp breaker without any issue however if hard starting you can go 20 amp but becarefull with conductor distance the voltage drop will affect the motor performace so stick with #12's that is good up about 150 feet total run if more than that you have to upsize it to compensate for the voltage drop.
I was going to use #12's from the main panel to the new subpanel to power the 220v well pump and one 110v circuit, but am reconsidering a larger size. Additional circuits from the subpanel:

(1) 300 ft to a barn for lights and a water tank deicer (total 8 amps load)

(2) 200 feet to another outbuilding for lighting and a GFI outlet (total 2 amps load)

Would #10's from the main panel to a 30 amp subpanel power the 220V well pump (8 amps), a pumphouse 110V light/outlet circuit (2 amps), and (1) and (2) above?

Would #12's from 20 amp breakers at the subpanel to each of the two outbuildings be large enough to meet the identified 8 and 2 amp loads? Thanks, Dave
 
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Old 10-13-09, 06:55 AM
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On the 300 ft run of #12 your voltage drop would be 9.5 at 8amps which would be border line at best. OK for lights but no motors. Go over 8 amps to say 15a and way to much voltage drop. Suggest a minimum of #10 on the 300ft run. Even then at 15a you would be looking at an 11.2 v drop. Ok for lights but marginal for motors.
 
  #16  
Old 10-13-09, 07:40 AM
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Thanks Ray, For next year or two the only load at the future barn location would be lights and a water tank deicer. Currently we only have a shelter. Later we'll build a barn and connect the electrical to a house panel which will shorten distance to 150 ft and allow more load. We will pull #10s from subpanel at the pumphouse to the shelter location.

Back to this question...Would #10's from the main panel to a 30 amp subpanel power the 220V well pump (8 amps), a pumphouse 110V light/outlet circuit (2 amps), and (1) and (2) above? Is 30 amp breaker and #10's enough?
 
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Old 10-13-09, 09:30 AM
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Yes #10 on a 30a 2-pole breaker should be fine to the pump house. Give you a bit extra to play with. Remember electric is like money once you have it you find uses for more of it. The temporary #12 to the barn at 300 feet would be OK for lights but I wouldn't try to run something like a circular saw on it.
 
  #18  
Old 10-13-09, 11:07 AM
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Got it! No motors!. That will be the generator's job as needed for the next couple years. Thanks all. Dave
 
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