SHANGHAI - As visitors rejoice in the festive atmosphere of the upcoming China Pavilion Day on Oct 1, Yang Yaoguo cannot do so.

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As director of the electrical substation that powers the China Pavilion and the surrounding provincial pavilion complex, he understands his job is crucial to the pavilions being able to operate successfully.

To that end, he has been working round the clock at the electrical substation 15 meters beneath the China Pavilion, checking that if the facilities operate smoothly and carrying out maintenance and repair work when necessary.

He has to make sure that the transmission and distribution of electricity is stable enough to keep lights and other electric devices functioning at the pavilion, such as the lift and air conditioning unit.

"We cannot allow a single problem to occur," said Yang, 42, of the Shanghai Municipal Electric Power Company.

He said the China Pavilion and the neighboring provincial pavilions receive an average 200,000 visitors and consume 250,000 kWh of electricity a day, which poses a great risk of accidents and creates a huge workload for his team.

"We have conducted numerous tests and prepared all kinds of emergency plans," he said. "For example, we have made sure that the emergency exits at the pavilions will always function, even if there is a blackout or, in extreme cases, a fire."

Yang and his team have been under relentless pressure over the past eight months, before the Expo even opened, during which time they became known for seldom seeing daylight.

As a rule, Yang and his team work 24 hours a day. They start at 8 am and work through to the following day, before taking a day off to sleep at home.

While on duty, they have to make checks every two hours and there is little time to surface and see the sunlight. They usually have no idea what the weather is like, whether there is rain or sunshine.

"At the height of summer, when everyone else was seeking shade, we would have liked to be able to see the sun, because we have been deprived from doing so," said his colleague Guo Yu.

At night, when the Expo Garden is closed, their real work begins. "All the major checks and maintenance work take place at night, in order to be sure everything is ready for the next day," Yang said. They are at their busiest on important days like the opening of the Expo and China Pavilion Day.

Despite being so close to the China Pavilion, Yang has hardly been able to visit it. Although he knows the layout of every electric cable behind the walls or beneath the floor, he only has a vague idea of the exhibits that are housed inside it.