It was my understanding that no PPE was required for 240/120 volts and below. I least that is what I read in NFPA 70E.
PPE is always required, when the system is >50V.
A specific arc flash study is not required by NFPA70E for certain systems (e.g. <240V fed by a 'small transformer')
There is no industry accepted method for performing arc flash calculations for single phase circuits.
No study does not mean no PPE.
Use the NFPA70E task tables.