How did water get in switch room? Authorities press MTR on cause of massive blackout
Moisture seeping into power cable led to short circuit which plunged part of Central station into darkness earlier this month
The government has asked the MTR to look into how water was able to seep into a power cable resulting in a rare massive blackout at Central station earlier this month.
The power failure on June 7 was triggered by a short circuit inside a low-voltage switch room, which caused a circuit breaker to trip, an MTR spokesman said on Monday.
From about 3pm, part of the station was plunged into darkness, with the power failure hitting the concourse, platforms, escalators, a lift and 14 shops.
Most shops on the station concourse near World-Wide House, including a 7-Eleven store and Maxim’s Cakes, suspended business following the outage. It was only at 9.10pm that power was fully restored.
Train services were not affected.
The MTR spokesman said on Monday that electrical workers had later found marks of water drops on the surface of the power cable concerned, and believed that the water had led to the short circuit and the tripping of the breaker.
They believed the water entered the cable via damaged areas found on the cable surface.
The fire alarm and fire extinguishing systems also went off due to the smoke-activated electrical safety device.
The cable has been removed for examination.
These findings were submitted in a report to the Electrical and Mechanical Services Department on June 8.
The department said on Monday it had asked MTR to provide additional information on the source of the water drops and how the company had followed up on the case.
Department director Frank Chan Fan said: “Water shouldn’t have been seen in a switch room. But the question is, where [was] the water from, and whether it was the exact cause of the incident. We need to prove it in a scientific way.”
