An electrical engineer had to be rescued after falling in a 12-metre deep hole on a construction site.

The 56-year-old worker was about to inspect the electrical wiring at an unfinished building in Bangkok, Thailand on October 7.

He was talking to colleagues about the project and asking some questions about their progress when he stumbled on the power cord of a vacuum cleaner and fell on the hole.

The workers immediately called the rescuers to help them lift the man from the wet hole that has been recently filled with knee-deep water after rainstorms.

Luckily, he was still conscious after hitting the ground or he would have drowned in the dirty water.

The rescuers built a pulley system on top of the hole before a volunteer wearing a harness rappelled down to carry the man up.

They rescue operation lasted for almost an hour before he was brought to the hospital by paramedics.

The man suffered bruises all over his body but aside from that, doctors said he had no other serious injuries.

Speaking at the hospital, the engineer said he was grateful for the officers who rescued him.

He said: "I could not move my legs properly when I fell, but I was lucky I could communicate with them while waiting for help."

He is still recovering at the hospital, but the doctors said that he can go home after a few days.