15 amp plug from the manufacturer means that it should run on a 15 amp circuit. My guess is that the 1.5HP rating is highly inflated. For 115 volts from NEC T430.248 a 1.5 HP motor has a FLC of 20 amps.I'm confused on how to size this equipment 1.5 HP, 110 V, 18 amp.
#1 What does the manufacture specify?
#2 Whats the nature of this load, that's not a continuous 18 amps or it wouldn't have a 5-15p on it?
Definitely a 20A circuit min.
Otherwise 18*1.25 = 22.5 Amps -> 25 amps breaker 10 awg wire. 5-30p
I would use a 20 amp circuit but it should run on 15.It is not continuous load type. This is the link to the equipment exactly https://lagunatools.com/classic/sanders/6-89t/