Electricians carried out the final check on transmission towers over 380 meters above sea on Sunday before their trial run begins on January 7 on the Zhoushan Islands, east China's Zhejiang Province.

When working at height, electricians need to walk on transmissions lines with only 2.5 centimeters in diameter for hours amid strong wind, fog and low temperature.

Serving the China (Zhejiang) Pilot Free Trade Zone (FTZ), the 500-kilovolt power transmission and transformation project has set 14 world records, including the world’s tallest power transmission tower and world's first cross-linked polyethylene submarine cables.

Electricians examine circuits at heights of over 300 meters in Zhoushan, Zhejiang Province, January 6, 2019. The testing is the last before the circuits are put into operation, which will provide electricity for the Zhejiang Free Trade Zone.

Electricians examine circuits at heights of over 300 meters in Zhoushan, Zhejiang Province, January 6, 2019. (Photos: VCG, with captions from CGTN and China Plus)