SIXTY-ONE tenants were rescued by firemen during an early morning blaze in a 17-storey building in Wan Chai yesterday. Tenant Mr Chan Kwok-keung, 23, suffering from shock, and fireman Tang Yiu-kin, 22, who cut his wrist, were taken to Tang Shiu Kin Hospital where they were treated and discharged. Firemen said the blaze in Yau Kwong Building at 416 Hennessy Road may have been started by an electrical fault. ''We believe the seat of the blaze was the advertising sign on the ground floor that belonged to a first floor mahjong club, a spokesman said. ''Initial investigation revealed the fire might have been caused by a short circuit in the advertising sign, which was badly damaged.'' A fashion boutique at the building's main entrance was badly damaged. The mahjong club and a restaurant between the first and fourth floors were slightly damaged. Also blackened by smoke was the Wellcome supermarket in the basement.