Lorna Sommerville says a cheap knock-off USB charger saved her money, but almost cost her her son’s life.

She bought the knock-off charger for $10 from Paddy’s Markets as a gift for her son Daniel on his 14th birthday last Sunday but, by Monday evening, the device was a blackened wreck.

It exploded within centimetres of the teen’s head after he plugged it into his iPod and sat on his bed, messaging friends on the social networking app Snapchat.

Daniel's near-miss follows the death of mother-of-two Sheryl Anne Aldeguer, who was killed while wearing headphones inside a Gosford home. She was found with burns on her ears and chest after a faulty charger sent a high voltage through her body.

Ms Aldeguer was found dead by friends on April 23 and it is understood she had been talking on the phone to a friend in Dubai when she was killed.