Basra was placed under tight security measures Sunday with much of the southern Iraqi city's streets being cordoned off for a second day, after blasts the previous evening killed 45 people, dpa reported.
The southern city, comprised mostly of Shiite residents, has about seven hours of electricity a day, owing to limited power generation and high demand. Local government has instituted unpopular power rationing, saying it had little choice.
The previous evening, 45 people were killed and 185 injured in explosions which had not yet been clarified.
Reports indicated that an electricity generator blew up when it was connected to too many nodes, as people tried to utilize the device beyond its capacity.
At the same time, a car bomb and explosive device went off nearby, police officials said.
An investigation was under way and a press conference was to be held later Sunday to brief the news media.
Basra, some 550 kilometers south of Baghdad, sees electricity demand spike in the summer, when temperatures rise to 49 degrees Celsius or higher. Even in winter months, the infrastructure cannot meet needs.
In June, protests against the city's power rationing turned into large-scale unrest that prompted a tough police response, leaving two dead and over 15 injured.