A Sydney mobile phone store has been fined after it sold a faulty USB phone charger to a young nurse who was later electrocuted.

Sheryl Anne Aldeguer purchased a $5 phone charger that malfunctioned and sent a high-voltage electrical pulse into her earphones from a store in Campsie.

She was found dead by friends in her North Gosford home in April 2014.

Huadi Bi and her company Hua Yang Australia faced two charges each for selling the allegedly faulty phone charger and adapter.

The company today was fined $6000 by the Supreme Court in a civil action brought by NSW Fair Trading, despite the maximum penalty being $550,000.

Ms Bi received $18,000 in fines from a maximum of $55,000 and the company was ordered to repay $25,000 in court fees.

"We're a little bit disappointed with the financial penalty imposed, given what the maximum could have been,” Fair Trade Commissioner Rod Stowe said.

The court was told today “the offending of the defendants was serious.”

“It was aggravated by the fact it was committed for financial gain and without regard for public safety,” Justice Geoffrey Bellow said in court.

Since Ms Aldeguer’s death, thousands of dodgy phone chargers have been seized.

"NSW Fair Trading on a regular basis does sweeps of the market place and we particularly target those areas we've found these non-approved articles in the past,” Mr Stowe said.