Sizing wire and OCP device for wells

[crtemp]

I have a question on well pumps. I am looking at this http://www.mikeholt.com/newsletters.php?action=display&letterID=1502
and I'm a little confused. The only time I get into wiring motors is on well pumps. I have always gone off of 430.248 to determine how many amps I need to cover on my wells. Has never been a problem but I am just curious if I'm doing things correctly. Say on this example I would pull a 12-2 and put this on a 20 amp breaker. Is this good?
I'm a little unclear on the S.F. ratings. The above post talks about "For motors with an SF of 1.15 or more, size the OPD no more than 125 percent of the FLA". So what about this motor with a S.F. of 8.0?

 

[ActionDave]

You are good to go. There are very few well pumps for an individual home that need anything more than 12-2 and a 20A breaker.

All that stuff about service factor and overloads is for passing an exam, code dork discussions, or motors that are not related to simple well pumps.

 

[don_resqcapt19]

If the well head is some distance from the power source, you need to take a look at the voltage drop. You have 200' of conductor down the well, so a 10 amp load would have a 2.8% drop just on the conductor between the well head and the pump motor.