States the requirements for both self-healing and non-self-healing continuously rated a.c. capacitors of up to and including 2.5 kVAr, and not less than 0.1uF having a rated voltage not exceeding 1000 V, which are intended for use in discharge lamp circuits operating at 50 Hz or 60 Hz and at altitudes up to 3000m. Covers capacitors intended for connection in shunt or in series with the lamp circuit or an effective combination of these.