mystery blackout.

They were desperate to discover why emergency systems failed to prevent the Island-wide crisis.

The company's newly-appointed chiefs, president Mr. Garry Madeiros and senior vice-president Mr. Vincent Ingham, spent a second day at the plant in talks with engineers.

An explanation for the blackout, the first to hit the whole Island since 1983, had been expected by last night.

But Belco spokeswoman Ms Linda Smith admitted: "I think it will be several days before they know the exact cause.

"There are built-in factors in the system to prevent this kind of thing happening, and for some reason these didn't kick in.'' The crisis hit at 5.28 a.m. on Saturday. No electricity flowed from Belco until about 11 a.m.

Power was gradually restored around the Island, and the plant took on its full load at 8 p.m. By 11 p.m. all but three Belco customers had power restored.

Their supplies were back on yesterday morning.

"Our engineers feel that we're now in normal operations,'' said Ms Smith.

"Barring any unforeseen events we don't expect additional problems.'' Residents, many of whom slept in when alarms failed to beep, were kept informed by the official emergency radio channel, on the air until 1.15 p.m.

Broadcast stations and cable TV were disrupted.

Police, hospitals and the Airport, along with many major hotels and supermarkets, used emergency supplies to stay in operation.

But Hamilton was quiet as top stores were forced to close, losing a busy day's trading.

Most major hotels relied on emergency supplies, said the Bermuda Hotel Association spokesman Mr. John Harvey.

At Harbour Radio, a new diesel-powered generator kicked in. Back-up equipment also started up at the Aquarium, which suffered no losses.

The Longbird Bridge near St. George's could not open, but both of the Island's lighthouses remained lit with back-up generators.

Traffic lights were not working most of the day, but Police reported no accidents as a result.

Belco was thankful for the public's understanding, Ms Smith said. "It was a very bad day for everyone, but people were great.

"Customers were overwhelmingly co-operative, and we're very, very grateful for that.'' Hurricane Emily cut off power from 70 percent of the Island in 1987, she said.

The last time there had been a 100 percent black out was 1983, after a fire in the plant.

Belco has denied reports that a blaze or explosion caused Saturday's disaster.

Deliberate damage had been ruled out, said Ms Smith. "At the moment our engineers are trying to trace the problem. They're looking at the entire system. We lost one engine, which caused a cascading effect on the rest.

Whatever happened to that engine had a rippling effect through the plant, and that is not normal.'' Instead of other equipment taking up the load it had shut down. She said the company was also grateful to staff, some of whom had worked 20-hour days.

Mr. Hume Martin, executive director of St. Brendan's and King Edward VII Memorial hospitals, said emergency generators worked "beautifully''.

Kitchens had been hit, meaning patients had cereals for breakfast and sandwiches for lunch.

"But there was no adverse effect on patients and we came through it extremely well.'' Mr. Dennis Tucker, manager of Sonesta Beach hotel, said: "We coped rather well. Our generators kept emergency lights on and water flowing, and fortunately our ranges are all gas.'' MarketPlace executive vice-president Mr. Allan Doughty said all but one of the firm's seven supermarkets stayed open.

PW's chief executive officer Mr. William Cox said Miles supermarket was forced to shut, but other stores had stayed open.

Most local supermarkets had freezers which could hold food for 36 hours without power, he said.

Mr. Glenn Titterton, president of BF&M General Insurance, said he did not expect a flood of claims following the blackout.

The Premier, who toured the Island during the power cut, praised residents for their high spirits and commended Belco for its response to the crisis.

The blackout was a reminder of the Island's vulnerability, he said. Earlier this month Belco was allowed to raise prices by 2.75 percent, but denied permission for 3.5 percent rises in 1995 and 1996.

It said one reason the rises were needed was to replace old machinery.

Sporadic Cablevision problems continued in parts of Paget and Warwick last night, as the cable television company relied on gasoline-powered generators to help it serve some customers.