Approval of funds for the provision of electric lighting for the School was granted by the Government in March 1922. Building of the School Power Station, engine rooms and workshop on the main ridge began later that same year. By the following March, two large capacity alternators, belt-driven by Crossley 126bhp, horizontal diesel engines were installed in the engine rooms and the necessary electrical wiring of all buildings on the hilltop was completed. The School 'lights' were officially switched on for the first time by General Sir Claude Jacob, K.C B., K.C.M.G., Chief of the General Staff, at a special ceremony held on the evening of 3rd April, 1923.

At about 7.30 p.m., the General and Lady Jacob were escorted to the newly built Power Station and after a short welcoming speech by the Principal, the buildings were officially declared open by Lady Jacob. The General then turned on the main switch connecting the system to the generators. The party then proceeded in turn to the Girl's and Boy's Schools where all the children were seated at their desks in the dark with their form masters and mistresses present. All individual light switches had previously been turned to the 'on' position. The General then turned on the main switch and all the class rooms were flooded with light. There followed much cheering, loud cries and shouts of excitement from the boys.

The Chapel was visited next, the party entering by the main west door. The church was gradually flooded with light beginning with the chancel, followed in turn by the apse, the two side aisles and finally the nave.

Finally, the General and his party proceeded to No. 11 quadrangle in the Boy's Department, by the top of the steps leading down to the lower dormitories and, on the sound of a single "g" from the duty bugler, all the boys' barracks were simultaneously flooded with light. By this time, the boys had all assembled on the BD pavement to witness the event. The "Best School of All" was then sung and the Heads of School called for three cheers for Sir Claude and Lady Jacob to conclude the ceremony.

Sanawar hilltop remained lit up and a blaze of light that evening until 9.15 p.m., when "lights out" was sounded and he generators switched off. Thereafter, although there were occasional failures, the electricity came on for everybody on the hilltop at 6.00 a.m. in the morning and was switched off at 9.15 p.m. every day until the early 1970's, when provision of the electrical supply for the school was taken over by the Himachal Pradesh State Electricity Board and the School was connected to the national grid.