Queenspark Zoo Sub-station experienced a technical fault causing electricity outage in the CBD, parts of West Bank and in the Arcadia area.
The burst was caused by a failure on a 132 kB line. Technicians are on site investigating the extent of the damage.
Residents are urged to be patient as it may take hours to restore power and to switch off all electricity appliances but treat them as live at all times.
Affected areas include; Quigney, Southernwood, Selbourne, lower part of Vincent, Bunkers Hill, lower Berea, North End, Belgravia, Parkside and Braelyn.