The Fire Services Department said it will work with CLP and the police to investigate what caused the fire on a cable bridge, that eventually collapsed, in Yuen Long that led to a power blackout of around 160,000 households on Tuesday night.

However, Hoi Wai-ming, deputy chief fire officer in New Territories North, told Commercial Radio on Wednesday that a probe cannot begin until after the collapsed bridge is reinforced.

He said incidents of similar scale and nature had not been seen in the past two decades, and the collapsed bridge had made it even more difficult for firefighters to put out the blaze.

“You’ve seen how the bridge had collapsed in the middle of the fire. It was difficult for us to assess whether it will collapse more. In addition, there were high-voltage cables in there. Around 130,000 watts. These elements have presented great difficulties for us,” Hoi said.

The officer explained that a fire-fighting robot was put into use because it could detect the temperature inside and eject water as well as transmit high-resolution images.

He added that the blaze had caused a huge number of other incidents – including more than 80 reports of people trapped in lifts and around 21 fire alarms going off.

Personnel and fire engines from other parts of the city were deployed to help with rescue efforts, he said, noting that no one was injured in the fire or in the other incidents caused by the power cut.

Secretary for Security Chris Tang said on Wednesday it doesn't appear the blaze involved foul play.

"The initial understanding is that the entrances to the bridge area were not damaged. At this stage, we don’t have evidence to suggest that someone deliberately went there to damage it."

Tang said the authorities will continue their probe to find out what caused the fire.

Edward Lo, a member of the Institution of Engineers, told an RTHK programme that several factors may cause a power cable to catch fire.

“There are three elements in electricity – voltage, current and resistance. For a cable to catch fire, one of the possible reasons is overloading, meaning the current is too big,” he said.

“We all know that it’s been rather hot these few days. Yesterday was also the summer solstice, and it was in the evening. Usually in Hong Kong, around 6 pm to 7 pm is the peak hour for electricity usage. Especially because it was so hot yesterday, people go home and turned on the air conditioner, but offices were not closed yet and their air conditioners were still on.”

“The current could have become too big, and if it went undetected and became overheated, it may catch fire,” he explained.

The expert said a sudden jump in voltage caused by factors like lightning could also lead to fire, as well as resistance being too high or too low – which could be caused by wear and tear of the cable.
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Last updated: 2022-06-22 HKT 15:01