A teenager who was electrocuted while installing insulation under a government scheme wasn't given any training or protective gear, a Brisbane court has been told.

Rueben Barnes, 16, was one of three Queenslanders killed while installing insulation in 2009 and 2010 under the federal government's axed Home Insulation Program.

Rueben's death was the focus of the first morning of a coronial inquest into the three deaths in Queensland on Monday.

The first-year carpentry apprentice was killed in November 2009 while he was installing fibreglass insulation batts in the ceiling of a home near Rockhampton.

He collapsed after coming into contact with a metal part of the ceiling that was live as a result of an electrical fault in the house.

Rockhampton workplace health and safety investigator Sara Francis told the Queensland Coroners Court neither Rueben nor two other workers on the job received any formal training from employer Arrow Property Maintenance.

Rueben and one of the other workers had been employed by the company for just three weeks before the fatal incident, she said.

Barrister Bill Potts, for Rueben's father, asked Ms Francis whether Arrow had provided them any standard safety gear such as arm guards, gloves, safety glasses or rubber-soled shoes.

She answered no.

"It seems from their answers that the only thing they provided was sunscreen," Mr Potts said.

"That's correct," Ms Francis replied.

"All he had was sunscreen and a pair of Crocs," Mr Potts said.

"Yes," she replied.

Matthew James Fuller, 25 and Mitchell Scott Sweeney, 22, also died while working on the same insulation program in 2009 and 2010, when they shot metal staples into live electrical cables.

The inquest will be held for one week, with a further three days set down in early May.