San Francisco is on the verge of amending its building code to require new construction to use only electric power. On Nov. 10, in the first of two required votes, the city’s Board of Supervisors voted 11-0 for the all-electric ordinance. At press time, the supervisors were scheduled to vote a second time. If the ordinance passes as expected, contractors would have until June 1 to file for building permits under the old rules.