The no of installed incandescent light is not equal the the no of fluorescent light of same power because of the role of chowk in the fluorescent lamp wiring. chowk works as a controller in this kind of wiring. Supposewe want to instal fluorescent light instead of incandescent light and the rating of the sub wiring is 5 Amp and the supply Voltage is 220 Volts. Thenthe no of 75 Watts fluorescent lamp will be find by this rumus.