This is the dramatic moment a quick-thinking grandmother saved an electrocuted man's life - using CPR she learned from YouTube.

Sangiam Kuekkong, 82, had hired the electrician, Somsak Kaerattana, 61, to fix a short circuit at her home in Chonburi, eastern Thailand, on July 8.

However, while he was fiddling with wires on the roof, Somsak accidentally touched an electrified metal gutter, sending a powerful shock through his body.

CCTV footage shows Somsak convulsing on a stepladder, unable to remove his grip from the gutter, with the loud noise drawing Sangiam outside.

Upon seeing the man shaking uncontrollably, she rushed over and tied a rubber cable around his ankle to drag him down. She then administered CPR, rhythmically pumping Somsak's chest until he regained consciousness.

In true grandmother fashion, Sangiam then asked the injured man if he wanted a drink and doodled away to make a cup of tea while they waited for the ambulance to arrive.

The local rescue team said they received a report at around 1:30 pm. They arrived at Sangiam's house and found Somsak conscious but severely weakened, lying on a wooden bench in the patio.

Somsak was rushed to the emergency room of Sattahip Km 10 Hospital and was reported to be out of danger.

Meanwhile, the heroic grandmother Sangiam said: 'There was an electrical short circuit in the house, so I hired Mr Somsak, who is an electrician who comes regularly to fix the wires.

'After the repair was complete, while Mr Somsak was going down the stepladder, his hand grabbed the gutter, which I believe was touching the electrical board connected to a power pole in front of the house. That was what shocked him.

'I was worried I could be electrocuted when I touched him. But I knew I had to help him. He has been a loyal repairman for me for a long time.'

The pensioner added that she had previously looked up CPR techniques on YouTube.

She said: 'I watched a video on my phone explaining how to help someone who is unconscious. I thought it might be useful and it has.'

After the scare, Sangiam visited the electrician at the hospital and assisted his family in taking care of him.