The subject of electricity crackled in San Francisco, New York and Miami yesterday.

Tourist-jammed restaurants on the San Francisco waterfront had to serve dinner candlelight; in New York an electric company official said a major emergency was never declared during last month's wideespread blackout, and a consumer boycott over Florida rate increase failed to faze the electricity and telephone companies.

An exploding transformer which blew a manhole cover 30 feet in the air, was blamed by Pacific Gas & Electric Co. for an 80-minute power failure on the Embarcadero. About 50 businesses in a four-block area were affected.

Chief system operator for Consolidated Edison, Charles Durkin, told a special public hearing that the New York power pool failed July 13 to declare a major emergency which would have required severe corrective steps. Con Ed claims it did not receive an order to shift to other power sources until too late, despite strong suggestions from power pool operators which are contained in taped telephone conversations.

In Miami backers of a one-day consumer boycott say half a million persons or more participated. But Florida Power & Light Co. and Southern Bell Telephone Co. said business was as good as usual, if not better.

FPL recently received a $195.5 million rate increase, while Southern Bell was granted a $133.6 million boost.