Am I required to wear arc flash protective clothing when throwing a 4160V disconnect? The disconnect feeds an air compressor that is turned off and there are no exposed live conductors at the disconnect.

70E does not provide for "no PPE". The minimum that it specifies is nonmelting fabrics which most folks don't really count as PPE but it effectively is.

In the tables there are many cases for equipment like you describe that CAN be considered H/RC 0 because the likelihood of an arcing fault performing the activity you are referring to is around 10^-6 failures/year. If you do the risk analysis, the answer is most likely that it is a tolerable risk.

That's not to say that there is NO arc flash hazard. But if you look at the notes under the definition of arc flash hazard, the likelihood of an arc flash is remote if the equipment is operating normally.

Based on your question I will assume you have not completed an arc flash analysis, so using the PPE tables from NFPA 70E, a >1kV metal enclosed switch with the doors closed requires HRC2 PPE.

yes, you need electrical protective safety clothing or equipments, you should never take risk,so dress up with your all necessary safety equipments.