His grandson was taking his usual shower in the evening when suddenly, he started screaming.
Shocked, the family rushed to the door, only to find it locked.
Beside the door, an electrical socket connected to the water heater was smoking.
When they finally battered the door open, 18-year-old Gregory Ng was on the floor.
"We turned off the electrical switch and went to his side," said his grandfather, Mr Anthony Ng, 62, a taxi driver.
His face was very pale by then, Mr Ng told this reporter from their Hougang Avenue 3 flat last night.
The incident happened around 10 pm on Friday. Gregory, a recent graduate of the Institute of Technical Education who was waiting for his National Service call up, was unconscious when the ambulance took him to Changi General Hospital. He died shortly after.
A Singapore Civil Defence Force spokesman said he died of a cardiac arrest.
He was cremated yesterday afternoon.
When The New Paper visited, his grandfather explained that the young man lived with his grandparents, his aunt and his two younger brothers in the three-room flat since he was a young boy, after his parents' divorce.
Recalling the tragedy, Mr Ng says that before the shower, Gregory had told his grandmother he'd talk to her after his bath.
Gregory's younger brother and aunt tried to perform cardiopulmonary resuscitation with instructions from the rescuer on the phone, but to no avail.
Gesturing to the water heater, which was connected to the socket by a wire, he said that they had bought it recently to replace an old one which wasn't working. He said he chose a branded heater based on the recommendations from the shop.
He was heard saying: "I spent more than $300 on the water heater and it killed my grandson."
Electricians contacted were reluctant to speculate on the causes of the electrocution but said it was extremely rare.
They explained that generally, an electrical surge would trip circuit breakers and shut off the electrical mains. But if the wall socket was smoking, it could be a sign that this did not happen.
The police have classified it an unnatural death and said they are investigating.
Mr Ng said his grandsons no longer dare to use the water heater when bathing.
He said: "They've asked their grandma to boil water using the kettle and bathe using a pail."
This article was first published on Aug 31, 2014.
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