While the Electrical Trades Union (ETU) has welcomed the company's decision to roll out the devices across NSW, it criticised the company for taking longer to do so than Ausgrid and Endeavour Energy, who it said deployed the devices for their field staff last year.

The union had been campaigning for the devices to be available to crews on all electricity network trucks following the death of Essential Energy worker Trevor Tooze on the mid-North Coast in September last year.

"Trevor was working on an upgrade of high-voltage power lines when an electric shock stopped his heart," ETU NSW secretary Steve Butler said.

"His colleagues performed CPR, but because of the remoteness of the work site it took more than half an hour for an ambulance to arrive.

"The first thing paramedics did was place a defibrillator on him, but unfortunately it had already been too long and they were unable to resuscitate him.

"A portable defibrillator on his work truck would have allowed treatment within minutes, which evidence shows would have greatly increased his chances of survival."

Mr Butler said the union had commissioned independent research which found portable defibrillators could mean the difference between life and death, and also met with former energy minister Chris Hartcher and lobbied power companies to act.

Essential Energy told the Daily Liberal it was in the final stages of its company-wide roll-out of Automated External defibrillators (AEDs) across its network distribution area, which had followed a successful six-month evaluation.

"The evaluation included a thorough risk/benefit analysis of defibrillator take-out rates and specific operational requirements associated with deploying the equipment across Essential Energy's large geographic footprint," Essential Energy's general manager health, safety and environment David Nardi said.

"Importantly, this evaluation also involved feedback and consultation with our employees on the most appropriate deployment of defibrillators.

"The 186 AEDs have been allocated to selected depots and offices in more than 100 locations throughout regional and rural NSW.

"As part of the roll-out, Essential Energy has provided field employees with face-to-face training in operating the units, while office staff will receive on-line training."