CHICAGO, JULY 29 -- Looting broke out again tonight after stores on the West Side were ransacked the previous night following a generating plant fire that left 40,000 customers without electricity, authorities said.

There were sporadic reports of looting tonight but no arrests were made, police said.

"We've got enough troops now. We've got them on the run," said police Sgt. John McDonald, adding that the number of police on streets in the affected area had been increased to 300 from the 100 deployed Saturday night.

Police said they arrested 49 people on looting-related charges Saturday night after power was knocked out. About 15 stores were ransacked, said Detective Luby Novitovic, who cautioned that it was a "rough estimate."

Three people died in a fire started by candles they were using to light their home, authorities said.

Power was restored to about 20,000 customers by 4 p.m. today, said Commonwealth Edison. More police officers patrolled the West Side to prevent a repetition of Saturday night's troubles.

Commonwealth Edison spokesman Bill Harrah said late today that no significant restorations of power were expected until at least Monday for the remaining affected customers.

Of Saturday's looting, Officer Rory Ohse said, "They {looters} just lined up outside the stores, waiting for the police to leave. As soon as the police left, they came back. We couldn't keep up."

But city officials played down the disturbances, saying they didn't expect major problems today.

"There is no need for a curfew. There is no call for the National Guard," said Mayor Richard M. Daley. "It was only a blackout. There was no riot. There was no heavy looting."

The blackout stemmed from a series of small explosions that began shortly after 10 p.m. Saturday in a faulty transformer at a coal-burning plant on the West Side, said John Hogan, another Commonwealth Edison spokesman. The resulting blaze knocked out the cables that route power to most of the West Side. The blaze was not extinguished until 6:30 a.m.

Crews continued to work to restore power, but some of the 20,000 customers without electricity will have to wait until Monday and possibly longer, according to Hogan.

Looting began in West Side business districts within minutes after the blackout and continued until sunrise, police said.

Some stores were ransacked and some completely emptied, business owners and police said. Vandals smashed glass doors and windows, and some chopped holes in the roofs of stores to gain entry.