EMB-190 Captain reported an FAA Inspector asked to see a NOTOC for HAZMAT that was loaded on board. The reporter stated Ground Operations had notified the flight crew of the HAZMAT; which was a process allowed according to the FOM.

Narrative

While we were doing our preflight duties for flight to ZZZ we noticed an FAA Inspector on the Ramp with a clipboard. We were told by Ground Operations that he was supervising the loading of a battery powered wheelchair with a non-spillable battery (which is considered HAZMAT). After boarding was complete the inspector came up to the flight deck and asked to see a document he referred to as NOTOC. I was unfamiliar with this document so I called Dispatch for clarification. The Dispatcher was also unsure and referred me to the Duty Pilot. After browsing the FOM and the Manual with the help of the Duty Pilot; we were unable to find a document labeled NOTOC. The only reference to this acronym was in the Manual; which said it stood for Notice to Captain." There was a note in the FOM stating; "When accepting any battery-powered wheelchair/mobility aid (including those powered by lithium-ion batteries) as checked baggage; the PIC must be advised either orally or in writing prior to departure as to the location of the battery aboard the aircraft." I told the FAA Inspector that I was made aware orally by Ground Operations that they were loading a battery powered wheelchair into the forward baggage compartment. He left and we departed for ZZZ without incident."