An electrical explosion sent blue sparks flying and workers running out into the street in Hamilton on Tuesday afternoon.

The loud blast was caused when a tap connected to a transformer near Atlantic House on Serpentine Road burnt out just before 2.30 p.m.

Almost 300 customers suffered a power cut, according to power supplier Belco, with all but 25 back on in the first 55 minutes.

Workers at nearby businesses told The Royal Gazette they heard a huge bang and rushed outside to see sparks in the air.

Construction worker Patrick Caines, who was in the new office block behind the Quickie Lickie laundromat, said: "Something fried! I saw a large bright blue flame flash into the building.

"It was just like a major vibration — thump! Now there is no electricity in any of the buildings. It's what we call equipment failure."

A male customer at Bermy Cuisine said: "I thought it was a bomb going off. There was a really big explosion. All the people came running out of their offices."

Joey Furbert, 18, who works at Bull's Head Car Wash, said he heard the explosion over the noise of the power wash. "She was really loud!" he said. "Everybody stopped what they were doing and just came out. Cars stopped around the roundabout. Everybody just stopped, froze."

PW Marine worker Chase Brangman, 19, said he was working on the computer when the power went off. "I heard a transformer bang. I knew what it was as soon as I heard it. We just closed the shop right away because we can't do nothing until the electricity comes on."

Nicole Butterworth, a consultant at Troncossi Public Relations in the Whitehall building, saw the telegraph pole outside the property shake.

"One of our delivery guys was walking past when it went and it scared the hell out of him," she said. "The power surged for a slight second and then it went off."

Belco spokeswoman Susan McGrath-Smith said: "There was a tap that burnt out at 2. 29 p.m. connected to a transformer near Atlantic House. Taps do burn out occasionally, and like this one, it's usually due to normal corrosion because of weather.

"Two hundred and eighty nine customers were out originally, with all but about 25 back on in the first 55 minutes; some rerouting of power was done by our operations centre to get the majority on while repair work continued."