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Discussion Starter · #1 ·
I'm helping my buddy install his control box for his 5hp submersible pump that will used for the irrigation of his hay field.
The power company already brought power to the site within 10 feet from the well location and a 100A Meter/Main has been installed.
He needs to get his breaker installed, have the conduit and wire ran to the control box which will be controlled by a motor rated switch.
I haven't had to size a motor circuit in a while and I'll admit I'm a little rusty.
Hoping to have a little help in confirming the proper size and protection in material.

Circuit Breaker
I need to know what size breaker would be the right one for this pump.
The manual for the control box is saying to use a 60A breaker in the install.
According my calculations I'm coming up with a 70A breaker using the FLC of 28 for a 5hp motor. 28 x 2.5 = 70

Wire
I'm coming up with a minimum of #10 AWG THHN.
28 x 1.25= 35

CentriPro
Pump Control Box
Model: CB50412CR
HP 5, Volts 230

Control Box Specs:
5 HP
230 Volt
24 Amp
3450 RPM
27.5 S.F. Max. Amp
1 Phase
60 Hertz
1.15 Service Factor
3.7 KW
Continuous Duty
KVA Code: F

Any help in figuring this situation out will be greatly appreciated.
 

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Bilge Rat
motors and controls.........
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8,477 Posts
70 is the maximum allowed by code. There is no code minimum. 60 is perfectly fine.

#10 is the code minimum; based on experience, I'd go with #8.
 

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Discussion Starter · #4 ·
Since this install will need an inspection I'll probably stick with putting the 60A since that is what it's calling for and see what the inspector has to say about it.
The #8 wire also sounds like a good idea cause I know that by the calculations it calls for #10 min, but putting #10 wire on a 60A breakers just doesn't sound right to me. It wouldn't hurt too bad the upsize a little.
 

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Discussion Starter · #6 ·
I can't remember off the top of my head. I'll have to check on that later.
I remember him saying something around 200+ ft, but I'm not sure if he was talking about the depth of the pump.
The drilling company installed the pump not too long ago and left about 10 ft of #12 THW Submersible Pump cable out of the well.
 

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fertilizer distrubuter
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1,250 Posts
If it is 200 foot you have a 18 volt voltage drop. Why worry about your 15 ft of wire when most of the install is boned already.
 
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