Jonathan Crosby, 45, from Dickleburgh, Norfolk was working as an electrical overhead linesman at UK Power Networks (formerly EDF Energy Networks Ltd) in Diss, Norfolk, when the incident happened.
He was in a cherry-picker five metres above ground, removing an electrical transformer from the top of a pole connected to overhead power lines. As it was being removed, the transformer made contact with live power resulting in Mr Crosby receiving a fatal electrical shock. The incident happened on 9 November 2007.
The Health and Safety Executive (HSE) investigation found that fuses supplying the transformer had not been removed to cut the electricity supply while it was lifted by a crane and also being held by Mr Crosby.
HSE told Norwich Crown Court that UK Power Networks had fallen markedly short in ensuring high risk work on its electricity distribution network, much of it located at height, was carried out safely.
It had failed to devise and prescribe rigorous and up to date procedures for this work, failed to train its staff adequately and failed to take steps to check these procedures were effective and employees were following them.
UK Power Networks of Newington House, 237 Southwark Bridge Road, London admitted breaching Section 2(1) of the Health and Safety at Work etc Act 1974. It was fined £300,000 and ordered to pay costs of £219,352.09.
Judge Peter Jacobs said of the company: "They fell significantly short of the reasonable practicability standards and they must take responsibility for their organisational and operational failures. It is obvious that the work being done is very dangerous and the merest contact could result in electrocution or a fall from height."
HSE Inspector Toni Drury said after the case: "A family man has lost his life in tragic circumstances, which could have been avoided if essential safety measures had been put in place by UK Power Networks. This tragedy illustrates how dangerous work on or near overhead power lines is and it is imperative that employers ensure there are safe systems of work and that these are implemented and followed.
"There is no room for error when working with such high voltages. It is not only the person involved in such an awful incident that is affected but family and friends are often left behind to deal with the devastation."