For the most part these circuits are not fused, they come directly off the equipment fuse and can have fuses up to your larges horsepower. Ther has to be an arc flash issue.
I found this on
www.msha.gov 30 CFR § 18.47
Voltage limitation.
(a) A tool or switch held in the operator's hand or supported against his body will not be approved with a nameplate rating exceeding 300 volts direct current or alternating current.
