Your question's been answered, but I have some random thoughts. Broadway was nicknamed the "Great White Way" because of its impressive electric streetlights. There is an ABSOLUTELY WONDERFUL book, "The Age of Edison: Electric Light and the Invention of Modern America," by Ernest Freeberg. If you want to go even slightly beyond getting the date, READ IT. Edison's genius was entrepreneurial, not just in engineering. He didn't just develop the light bulb. He and his laboratories developed all of the infrastructure needed to light cities. The invention of the electric meter to allow electric companies to BILL for power was probably as important as the light bulb itself. They developed some interesting mathematics for the formulas for sizing electric cables--very heavy gauge (thick) near the central station, getting thinner as the tree spread out--to get the most economical compromise between power lost in the cables and the cost of the thick copper. The transition from gas to electricity had been proceeded by an EQUALLY dramatic technology revolution in gaslight itself--the transition from open flames to Welsbach mantles. The house I grew up in (in a suburb of New York City) actually contained a few lighting fixtures that had been gaslights that had been converted to electricity. The advent of electric light completely transformed the theatre. We are so used to the idea of stage lighting that it is impossible to imagine what they did before. Even today, what they do with stage lighting can seem magical--imagine what it must have been like when it was new.

It happened gradually, from 1880 onwards. Broadway was the first street in NYC to have electric lighting.