Applies to ballasts designed for the operation of hot cathode fluorescent lamps on a.c. supplies at a frequency of 50 Hz. It applies to complete ballasts and to component parts such as reactors, transformers and capacitors, which are incorporated int he ballasts or supplied as separate elements essential for the functioning of the ballasts in fluorescent lamp circuits. It does not apply to (i) ballasts of the resistance type; (ii) ballasts designed for use with cold cathode fluorescent lamps; (iii) capacitors which are incorporated in starters. The specification prescribes requirmeents for the characteristics of ballasts which are essential for proper lamp operation and also for the satisfactory operation of the ballasts themselves in fluorescent lamp circuits.