Incandescent and fluorescent lamps with and without an integrated ballast can be divided into energy efficiency classes. The division of lamps into such classes was made in EU Directive 98/11/EC on 27 January 1998, and includes lamps that are not marketed for use in the home. Light sources with an output of more than 6,500 lm and those that are not operated on line voltage are excluded. The energy efficiency class is determined as follows (Φ is the luminous flux in lm and "P" is the power consumption of the lamp in W):