An inquest into the death of a man electrocuted on a Top End prawn trawler has heard a safety switch could have saved his life.

Key points: Ryan Donoghue was using an angle grinder when the boat was hit by a wave

Ryan Donoghue was using an angle grinder when the boat was hit by a wave Power tool plugged into socket without safety switch

Power tool plugged into socket without safety switch Old boats excused from meeting electrical standards

Ryan Donoghue, 20, was using an angle grinder on the deck of Austral Fisheries' Newfish 1 to cut rusted shackles when he was hit by a wave and electrocuted.

Counsel assisting the Coroner, Kelvin Currie, told the inquest the grinder had been plugged into a socket without a safety switch, known as a residual current device (RCD).

Newfish 1 was about 11 hours from the Arnhem Land coast when the accident occurred in November 2013.

The Austral Fisheries vessel Newfish 1 operated in the Northern Territory, Western Australia and Queensland. ( Supplied )

"If such a device was fitted it would have cut the power to that circuit and would in all likelihood have saved Ryan's life," Mr Currie said.

"Ryan should not have been electrocuted. He certainly should not have died."

The inquest heard Mr Donoghue was not wearing shoes or any other safety equipment.

"This half decent wave came over the deck... he took about two steps back and fell flat onto his back. I realised at this time he was being electrocuted," deckhand Jeremy Hedger-Dunn said in statement read aloud during the inquest.

Mr Donoghue migrated to Australia from England in 1999 and lived in Melbourne during the off-season.

Mr Donoghue's father Steve said the family had travelled from Melbourne and England to the Darwin inquest, hoping for answers.

"My family and I are completely devastated by the death of our dear son Ryan," Steve Donoghue said.

"We, his family, find it completely unacceptable that anyone could die under these circumstances, given the strict occupational health and safety regulations that exist in this country."

The inquest heard audio from telephone calls between a doctor and crew members while they tried unsuccessfully to revive Ryan Donoghue with CPR.

The ship's electricity outlet that the power-tool which electrocuted Ryan Donoghue was plugged. ( Supplied )

Mr Currie told the inquest there was little evidence the RCDs on the trawler had been tested and "no unequivocal document" from an electrician stating that it complied with standards.

Despite this, jurisdictions in which Newfish 1 operated - the Northern Territory, Western Australia and Queensland - continued to provide certificates of survey and registration, according to Mr Currie.

"There are many vessels that do not comply with electrical," Ian Ritchie, an expert in electrical installations on boats, told the inquest.

"If you start to look at electrical too deeply, there's going to be political backlash. It's a can of worms.

"And it's a can of worms that they haven't had a desire to open."

Coroner Greg Cavanagh suggested that older boats were being excused from meeting electrical standards because of "grandfathering" arrangements under national laws regulating commercial vessel safety.

"No-one's really going to make a whole fleet of vessels comply with electrical standards because it's too expensive," Mr Cavanagh said.

Austral Fisheries operates 10 prawn trawlers across northern Australia and based its fleet in Darwin before moving to Cairns in 2009.

According to the Woolworths website, Austral Fisheries supplies the supermarket with 1,000 tonnes of banana prawns each year.

The inquest continues on Tuesday.