Date: 202101
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: VFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Emergency Equipment
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Training / Qualification; Workload
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Attendant
When detected: Pre-flight
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Procedure
Primary problem: Procedure

Narrative: We flew to ZZZ on aircraft X. We then were scheduled to fly same aircraft from ZZZ to ZZZ1 with a new flight attendant crew. When the flight attendants did their pre-flight; I was notified that the emergency equipment in the AFT bins were in the incorrect bins. They were in the opposite bins as depicted in the 737 diagram and the flight attendant manual. Apparently they were installed that way back in month when the modification was complete. The stickers that were on the bins depicting what emergency equipment was correct but the emergency equipment was on the incorrect side. I called dispatch who connected me to maintenance and they said couldn't find any diagram that would place emergency equipment where it was. ZZZ maintenance agreed that emergency equipment was installed incorrectly. The aircraft was taken out of service.The equipment was installed wrong. In is my understanding this airplane flew around since April like this. More emphasis on flight attendants checking proper locations of emergency equipment.More checks to make sure when there is an interior modification that it's installed correctly


Second narrative: Upon arrival a ZZZ; we received a new cabin crew for the flight to ZZZ1. ZZZ to ZZZ1 was to be the flight deck crew's second flight using the same aircraft.   During the pre-flight; the aft cabin crew called the flight deck and advised us that the emergency equipment that is stowed in the two most aft overhead compartments were not located in their proper location.  TO fully understand; I also went aft to see for myself.  The FA showed me in her manual; the proper location and orientation of the equipment.  I went back to the flight deck; verified the same information in the aircraft operating handbook.  I advised the Captain of the discrepancy.  Maintenance was called.   This discrepancy was found on the second leg of the day; while utilizing the same aircraft.  The location of the equipment was inverted in its actual location vs. the location as stated in the manuals.Cabin crew may have not been facing forward in the cabin when pre-flighting the emergency equipment.  While the equipment was stowed in an overhead bin correctly; with the proper associated placards; the actual location of the equipment did not match the location stated in the manual.  As an example Oxygen is to be in the port side overhead.  Its actual location was starboard.  It is possible that during a pre-flight that a crew member facing aft will simply associate that the oxygen is 'on my left side'   This aircraft also had new overheads and added capacity within the last year. During that change; the equipment may have been installed incorrectly. Cabin crew may need to have greater situational awareness as to the actual right and left side of the aircraft; regardless of their orientation within the cabin.


Synopsis: Air carrier FIrst Officer reported that Flight Attendants discovered Emergency Equipment was not reinstalled in the correct locations after an interior modification.