A power outage in Wong Tai Sin District, Kowloon, last month is said to have been caused by interference from third-party objects, prompting calls for tighter supervision of power facilities to mitigate the problem.

A report China Light and Power Company submitted to the Electrical and Mechanical Services Department on Tuesday showed that on the night of June 12, a cable joint of two 11,000-volt ring circuit cables in Wong Tai Sin had been subject to third-party interference, causing gradual deterioration in the insulation system, and the two cables breaking down.

CLP Power had experienced six power-related accidents in the first half of this year, caused by defective materials, inadequate supervision of contractors’ work, as well as equipment damaged by wildfires or thunderstorms

The power outage lasted more than four hours, affecting over 2,250 households. A number of residential buildings and shopping malls were blacked out, forcing shops to close early. Some residents were trapped in elevators.

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CLP Power had experienced six power-related accidents in the first half of this year, caused by defective materials, inadequate supervision of contractors’ work, as well as equipment damaged by wildfires or thunderstorms.

The company apologized for the disruptions caused by the Wong Tai Sin outage and outlined measures to prevent similar incidents, including strengthening inspections of cable lines and substations in the district, and reminding construction workers to avoid interfering with underground infrastructure.

The EMSD said it’ll study CLP’s report carefully to assess the adequacy of the investigation and whether the remedial steps to be taken are appropriate.

Legislator Michael Tien Puk-sun said residents shouldn’t pay the bill for CLP’s potential negligence in monitoring third-party projects near its power equipment and called for supervision procedures to be tightened.

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Lau Wai-chau, a spokesperson for the electrical division of the Hong Kong Institution of Engineers, said road construction in Hong Kong often leads to cable damage caused by external objects. He said evidence can be found if there’s interference from external objects.

However, cable damage may not occur immediately, but could manifest as faults after several years, making it difficult to assign responsibility, Lau said. The SAR government has enacted legislation in recent years, requiring developers to obtain permits and underground cable diagrams before undertaking road construction to ensure that workers can avoid underground cables in their operations.

Lau believes the issue lies in whether workers strictly adhere to these regulations, adding that the power company has a duty to step up inspections to prevent potential external interference and utilize advanced instruments in monitoring the situation.