B737 captain reported the generator was unable to carry aircraft electrical load.

Attributes
ACN	1636206
Time
Date	201904
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	Electrical Power
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Last 90 Days 180
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Other / Unknown

Narrative:

Completed brief with ground crew for coordination; checked hand microphone captain side during preflight with ground crew; due to inoperative APU and push to talk switch on captain yoke. Completed all checklist; cleared to start number 1; first officer (first officer) began to start number 2 in error; ground crew and myself recognized error and immediately aborted start of number 2. Completed checklist again and correctly started number 1. Generator on number 1 was unable to carry electric load for required configuration and would be unsafe to power up engine at gate; so start was aborted and ground; operations; and maintenance were advised. Parking checklist completed aircraft grounded by maintenance with write-up of number one generator and passengers were deplaned and put on another aircraft along with crew.

Original NASA ASRS Text

Title: B737 Captain reported the generator was unable to carry aircraft electrical load.

Narrative: Completed brief with ground crew for coordination; checked hand microphone Captain side during preflight with ground crew; due to INOP APU and push to talk switch on Captain yoke. Completed all checklist; cleared to start number 1; FO (First Officer) began to start number 2 in error; ground crew and myself recognized error and immediately aborted start of number 2. Completed checklist again and correctly started number 1. Generator on number 1 was unable to carry electric load for required configuration and would be unsafe to power up engine at gate; so start was aborted and ground; operations; and maintenance were advised. Parking checklist completed aircraft grounded by maintenance with write-up of number one generator and passengers were deplaned and put on another aircraft along with crew.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.