A power company worker was airlifted to hospital with severe electrical burns following a fire at a sub station near Alfreton.
Firefighters from Alfreton Fire Station were called to Nottingham Road in Somercotes at about 8.30am on Saturday morning.
The fire was out on arrival but first aid was given to the 46-year-old man who had suffered severe electical burns to his upper torso, hands and torso.
Police and paramedics were also called to the scene and the injured man was airlifted to Queen’s Medical Centre in Nottingham for further treatment.
A police spokeswoman said there were no suspicious circumstances surrounding the incident.
She added that the Health and Safety Executive are now working with Western Power to determine the cause of the incident.
A spokesman from Derbyshire Fire and Rescue Service said Western Power visited the site and isolated the supply while an investigation was carried out.
There are no safety concerns for residents living nearby.
Firefighters remained at the scene until 9.40am.