Let me get this right...

[4-20mA]

This fountain states it needs a 125amp 'inverse time' breaker or 80amp fuses protecting the motor. Ok, then at 125% motor amps, I get 58.75. So Ill have to go to a #4? 40°? What protects the wires?

I don't do calculations much so just doing some double checking. The motor thing with wires smaller than overcurrent device ratings have always made me scratch my head.

 

[augie47]

You actually use the Table 430.248 values which would be 50 amps but your numbers will still work.
#6 THWN or #4 Romex or UF
The controller overcurrent protection protects the conductor. You breaker (fuse) only provides short circuit protection.

You would need to confirm your contro; center provides GFCI protection or you breaker would need to be GFCI>

 

[ptonsparky]

The 125/80 amp are short circuit branch circuit protection. Not over current protection.