Cable blaze that sparked huge Hong Kong blackout likely to have been caused by fluorescent light that caught fire, says CLP
- Fluorescent light causing fire was ‘rare occurrence’, but such structures can overheat due to deterioration, according to report
- Blaze in Yuen Long plunged about 175,000 households and businesses into darkness
A blaze in June that sparked Hong Kong’s worst power outage in decades was likely to have been caused by a 30-year-old fluorescent light that caught fire inside a cable bridge, the electricity company involved has revealed.
CLP Power on Friday disclosed details of its final report two months after the cable bridge fire in Yuen Long plunged about 175,000 households and businesses into darkness, noting that no fire detection or protection system was installed inside the bridge.
“According to the investigation report, the most likely [cause of the blaze] is that the fluorescent light inside the cable bridge caught fire first, and then affected the communication cable underneath it,” CLP Power managing director Chiang Tung-keung said. “The fire spread to the transmission cable … and across the bridge.”
On June 21, the cable bridge carrying three high-voltage lines caught fire and collapsed, leaving homes, hospitals, businesses and the railway network across the western New Territories without electricity. Populated districts such as Yuen Long, Tuen Mun and Tin Shui Wai were affected.
Hong Kong company to remove bridge, finish laying cables week after fire
A fluorescent light causing a fire was “a rare occurrence”, but such products could overheat due to factors such as deterioration, according to the report. It added that the light tube was most probably switched on before the incident but it was difficult to determine as most equipment at the scene was damaged.
The power supplier added that the light tube has been in use since the cable bridge was commissioned in 1992.
“Normally, the light tube is not switched on when no one is working inside the cable bridge, so it only operates for a very short period of time over the years … During the last inspection, there was no abnormality,” said Eric Cheung Po-chung, CLP’s senior director of power systems.
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Bridge catches fire in Hong Kong, causing temporary blackouts in Yuen Long
The company added that it had replaced all fluorescent lights in four other cable bridges of similar design.
The light was installed below a beam within a section around four metres from the junction between the steel bridge and a concrete chamber on Kwong Yip Street.
The report excluded foul play, a glitch in the protection system and hot weather as causes of the fire.
Investigators also found that no fire detection or protection system was installed inside the bridge and only some parts of the cables had fire-retardant coating. The company only learned of the fire after it received a resident’s report at 7pm that day, half an hour after smoke was seen on the cable bridge.
The report also revealed that of the two backup power sources, one was under repair and the other could not be put into use right away because the communication cable that would trigger it had been damaged by the fire.
CLP said it had since installed heat detection systems, alarm signals and fire sprinklers in the other four bridges, and all cables inside had been painted with retardant materials that could resist fires for two hours.
Wilton Fok Wai-tung, principal lecturer for the electrical and electronic engineering department at the University of Hong Kong, said it was “not ideal” that the power company had not changed the light tube for such a long time.
“It will be best if CLP Power can switch to using LED lights in the future, which last longer and save more energy, while being safer,” Fok said.
Lawmaker Edward Lau Kwok-fan said CLP Power had to learn lessons and improve.
“Whether there is a human factor in switching on the fluorescent light abnormally, the company has not told the public,” Lau said, adding that the use of fire-retardant paint and fire detection devices was a basic requirement.
“CLP Power seems to have underestimated the safety risk as it only did remedy after the incident.”
The power company earlier said it would allocate HK$20 million to offer HK$100 vouchers (US$13) to affected residents in Yuen Long, Tin Shui Wai and Tuen Mun next month as compensation.
