Date: 201312
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Taxi
Aircraft component: AC Generator/Alternator
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Communication Breakdown; Human-Machine Interface; Troubleshooting; Training / Qualification
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural MEL / CDL
Detector: Person Flight Crew
When detected: In-flight
Result: General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: Upon review of the aircraft's AML I found an MEL for the engine driven generator Number 2. I read the MEL book and it mentioned that the advisory message GEN BRG FAIL may be present and we are dispatchable provided the Caution Message GEN OFF BUS was not present for the previous flight. The write up from the previous crew mentioned the GEN BRG FAIL message but not the Gen off Bus message. I interpreted that we were good to depart with the MEL. After pushback from the gate and starting of Eng Number 2; we got the message GEN 2 OFF BUS. I called Maintenance Control and informed him of the situation and he asked if Maintenance had collared two circuit breakers and deselected Gen 2 on the overhead. I said they had not. He said they should have and then instructed me two collar circuit breaker E8 and E9 behind the FO seat and deselect the Gen 2 on the overhead with which I complied. I believed that this brought us in compliance with our MEL. Doing this cleared the GEN BRG 2 FAIL message; but the GEN 2 OFF BUS remained. This made sense to me as it was now deselected. He also asked me if I was hearing the relays clicking I said they were not. I asked if we were good to depart with the GEN 2 OFF BUS message on the EICAS and he said I was. The MEL only mentioned it as a restriction if it was on the EICAS on the previous flight and made no mention of the current flight so I believed we were legal to depart.  We departed and; while enroute; I was reading over the MEL book on generator MELs. The MEL listed [prior] the one we had been MEL 24-31-01 which was for the Engine Driven Generators (not the bearings as was the one we had). The (Maintenance) items for this MEL mentioned all of the steps that I had done on the ground prior to our departure. I believe Maintenance Control was reading the procedures for the wrong MEL and that maintenance had correctly 'not' collared and deselected the GEN. Therefore the GEN 2 OFF BUS should not have been on the EICAS and we should not have departed. After landing I again called Maintenance Control and this controller said that the breakers should not have been pulled and collared and that GEN 2 should not have been deselected for our MEL. We then MELed GEN 2 which did instruct the circuits to be pulled and the generator to be deselected. I believe that it was just human error that resulted in this situation. The MEL numbers are very similar and mistakes can happen. I should have questioned more with Maintenance Control that the MEL book did not specifically mention the presence of the GEN OFF BUS message even though I expected the message given how the generators were [then configured].




Synopsis: Confusion reigned regarding a generator MEL item in the AML for the reporter's E-145 which resulted with the generators improperly configured. After reviewing the pertinent documents enroute the reporter contacted Maintenance Control with his discovery and the errors were corrected prior to the next departure.