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Old 02-07-2009, 01:07 AM   #1
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power to submersible well pump


I need to pull wire to a 1 hp 230V submersible well pump and want to avoid any major mistakes. Here is my plan, and by reading the numerous other threads here I know you guys won't be bashful, so I am prepared.

The pump uses 11 max amps. I have a 240V circuit (30 amp breaker) that runs 20 feet directly to a dryer outlet. I switched to gas so the outlet is not used. I plan on installing a GFIC breaker in the 30 AMP spot on the main panel. I would like to wire the pump from the dryer outlet (if that is acceptable) or I can take the dryer outlet out and wire straight to the breaker box. The distance from the outlet to the pump is 250 feet (270 if I go straight to the panel).

It looks like I need 3 #8 thwn wires and a ground that I will run 18 inches deep in rigid 1 1/2 (I may pull a second 120 circuit in the same pipe) PVC using two pull boxes on the route as I have two hills to contend with.

My questions are

1. What size gound wire should I use?
2. Do I need any other grounding (gound rod)?
3. Is my wire size correct?
4. Do I need to start from scratch?

Thank you in advance.....

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Old 02-07-2009, 07:30 AM   #2
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power to submersible well pump


1) #10
2) No
3) Sounds good to me although #10 would only be about 2.5% voltage drop

As far as using the dryer, you should remove the receptacle and install a junction box (wasn't sure if that was your plan).

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Old 02-07-2009, 08:43 AM   #3
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power to submersible well pump


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Originally Posted by wirenut1110 View Post
1) #10
2) No
3) Sounds good to me although #10 would only be about 2.5% voltage drop

As far as using the dryer, you should remove the receptacle and install a junction box (wasn't sure if that was your plan).

Wire has gotten much cheaper in the last two months. I'd run it the extra 20 feet right to the panel. Jamie
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Old 02-07-2009, 08:49 AM   #4
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430.22 Single Conductors to a single motor must not be sized smaller than 125% of the FLC rating.

Motor FLC =8.0A [Table 430.148]
Conductors Size = 8.0 x 1.25
Conductors Size = 10A, 14 AWG, Rated 20A at 75degrees [Table 310.16]


430.52 Branch-Circuit & Ground Fault Protection
Protection Table 430.52
FLC x 250%
8.0 A FLC x 2.5 = 20A


With that said your MINIMUM requirements are #14 AWG supplied by a 20 amp breaker.

#14 AWG is good for 250'
#12 AWG is good for 400'
#10 AWG is good for 630' with a 5% voltage drop. But regardless of what size wire you choose, your MAXIMUM breaker will be 20A.
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Old 02-07-2009, 09:25 AM   #5
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Chris

That might be the best post I've seen for sizing a well pump ocpd and conductors. Plain and simple.

ERLINBL

Only thing I'll add is whether or not the pump is 3 wire or 2 wire. You say your wanting to run directly to the well pump from the breaker box so I am assuming you have a 2 wire well pump that does not have a control box. If you have a 3 wire pump you need a control box. You were not clear so thought I would ask. I'd run an all new pump motor circuit and forget the dryer deal regardless.

Just for curiousity can you give us the pump motor brand and model#?
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Old 02-07-2009, 09:40 AM   #6
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Chris

That might be the best post I've seen for sizing a well pump ocpd and conductors. Plain and simple.
Thanks, and sorry I didnt back to you on your PM either, still trying to digest that section.
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Old 02-07-2009, 10:03 AM   #7
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Thanks, and sorry I didnt back to you on your PM either, still trying to digest that section.
I wasn't expecting anything soon.... I'm still trying to digest it myself.... It almost reads to me like if you configure 6 double pole breakers they must take up all the spaces of the panel in order to be a 6 disconnect...
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Old 02-07-2009, 11:59 AM   #8
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Originally Posted by Stubbie View Post
I wasn't expecting anything soon.... I'm still trying to digest it myself.... It almost reads to me like if you configure 6 double pole breakers they must take up all the spaces of the panel in order to be a 6 disconnect...
Thats exactly the way I read it also.
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Old 02-07-2009, 02:42 PM   #9
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I was going by his saying 11 amps and 1 HP.(Thought that was nameplate) and that's what would be used when both are given. Which would still be min #14 but 250% OCPD would be 27.5 amps.

PS If amps are given then the corresponding HP on the table should be used which would put it up to 2 HP.

Last edited by wirenut1110; 02-07-2009 at 03:11 PM. Reason: Added PS
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Old 02-07-2009, 02:59 PM   #10
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Wow, thanks for all the responses. I have not bought the pump yet but I am looking at the Betta Flo BF-2008 which was recommended to me on a well pump and tank forum.

So I will take the dryer receptacle out of the loop and go straight to the panel with a 20 amp GFIC breaker. I noticed that the 240 running to the dryer is in flexible conduit. Do I need to run my wires that enter the house in the flexible conduit for code?

Edit (Also, what size gound wire should I run?) Sorry it says it three times. I should have woken up more before replying...

Thanks again....

Last edited by erlindbl; 02-07-2009 at 03:06 PM.
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Old 02-07-2009, 03:09 PM   #11
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Originally Posted by wirenut1110 View Post
I was going by his saying 11 amps and 1 HP.(Thought that was nameplate) and that's what would be used when both are given. Which would still be min #14 but 250% OCPD would be 27.5 amps.
You never use the nameplate for conductor sizes or ground fault and short circuit protection, You DO use the nameplate for overload protection, which by the way is already installed in the motor.
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Old 02-07-2009, 03:14 PM   #12
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Originally Posted by erlindbl View Post
Wow, thanks for all the responses. I have not bought the pump yet but I am looking at the Betta Flo BF-2008 which was recommended to me on a well pump and tank forum.

So I will take the dryer receptacle out of the loop and go straight to the panel with a 20 amp GFIC breaker. I noticed that the 240 running to the dryer is in flexible conduit. Do I need to run my wires that enter the house in the flexible conduit for code?

Edit (Also, what size gound wire should I run?) Sorry it says it three times. I should have woken up more before replying...

Thanks again....
First off, you dont need GFCI protection. Your ground wire shall be sized according to Table 250.122,

15 amp breaker gets 14 AWG
20 amp breaker gets 12 AWG
30 amp breaker gets 10 AWG.
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Old 02-07-2009, 03:16 PM   #13
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power to submersible well pump


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Originally Posted by chris75 View Post
You never use the nameplate for conductor sizes or ground fault and short circuit protection, You DO use the nameplate for overload protection, which by the way is already installed in the motor.
I believe there's an exception (book not available at the moment)that says if both are given (HP & FLA) then that has to be used for disconnecting means, branch circuit conductors, controller, branch circuit short circuit and GF protection.

Not that all this is a big deal anyway. I'm not a huge code guru anyway.

Last edited by wirenut1110; 02-07-2009 at 03:20 PM.
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Old 02-07-2009, 03:30 PM   #14
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If the nameplate amps is available, you must use the larger of either the codebook table amps or nameplate amps.

In all the motors I've connected in the last 19 years, I've yet to see one (of normal speed anyway) that has a larger nameplate amp rating than the codebook table.

With VERY few exceptions, the codebook table amps will govern the wire size selection.

Rob
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Old 02-07-2009, 03:39 PM   #15
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If the nameplate amps is available, you must use the larger of either the codebook table amps or nameplate amps.


Rob

Rob do you have code section handy?

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