Cannot comment on 737
In general for smoke of an electrical nature the procedure is to isolate each electrical bus individually. Starting with the AC buses.
Isolate number 1 generator wait to see if smoke ceases if not reinstate. Isolate next generator on so on. If smoke not caused by equipment powered by ac bus bars procedure will move you on to dc bus bars fed from TRUs.
If fault not on thoses bus bars then procedure moves to battery fed bus bar.
Procedure is designed to isolate in sequence all bus bars hence electrical equipment,whilst maintaining supply to the rest of the sytems, in a sequential order. Eventually coming to the source of electrical smoke.
If you come to the end of the procedure and have failed to isolate system then you have either carried out the procedure incorrectly
or you have Air Conditioning smoke
have seen that happen on the Simulator. But that is another story
