Need Help Prepping for My Final

[TrayLo1201]

Hey everyone, so I am studying for my final and I'm getting zilch help from my instructor. I have read and re-read the A430 in the NEC and googled till I'm blue in the face. I need help with the following question:

A single phase 2 HP motor running at 13.2 amps is to be installed at a distance of 275ft from its branch circuit OCPD. What's the minimum size conductor required to stay within the NEC recommended guidelines for this installation?

The answer key says #8AWG, so the answer after calculating must be between 30-40 amps, right? Yet I cannot calculate to land my calculation answer between these ranges. Any help is greatly appreciated!

 

[GoldDigger]

First you need to know what the NEC guidelines are.
Caution, the answer is not in a table or formula but in an informational note.
It is NOT a requirement. As the instructor was careful to state, it is just guidance!

The current is not increased because of the distance, but the voltage drop in the wires is.

Sent from my XT1585 using Tapatalk

 

[augie47]

2HP @ 13.2 amps would indicate its a 208v motor.
Taking NEC recommended voltage drop of 3% and applying the VD formula:

CM= 2 X R X I X L

CM = 2 X 12.9 X 13.2 X 275
6.24
CM= 93654/6.24 = 15008
#8 @ 16,510 CM would be required

#8 would be a plausible answer

 

[TrayLo1201]

Thank you

Thank you

Thank you guys for the help. Greatly appreciated!