The demolition of a coal-fired power station where four workers were killed caused a power cut affecting about 40,000 people, energy firm SSEN said.
Cooling towers at the disused Didcot plant in Oxfordshire, owned by German group RWE, were taken down early on Sunday morning.
Christopher Huxtable, 33, from Swansea, South Wales, Kenneth Cresswell, 57, and John Shaw, 61, both from Rotherham, South Yorkshire, and Michael Collings, 53, from Saltburn-by-the-Sea, Teesside, died after the partial collapse of the boiler house at the Didcot A plant in February 2016.
Thames Valley Police and the Health and Safety Executive had launched a joint investigation to consider corporate manslaughter, gross negligence manslaughter and health and safety offences.
An SSEN spokesman said they received reports of damage to their network at Sutton Courtenay shortly after 7am on Sunday, following the demolition of the nearby power station.
Engineers attended the site to make the situation safe and power was fully restored to the 40,000 customers affected by 8.20am.
“Initial investigations have confirmed that this morning’s power cut was caused by material related to the demolition of Didcot Power Station striking our overhead electricity network,” a spokesman said.
“During the demolition, a large section of debris protection material became detached from one of the cooling towers and made contact with our 33kV overhead line, which was outside of the advised perimeter.
“This resulted in significant damage to the overhead line and subsequent network faults.
“We are in contact with the station owner, RWE, to support them in their incident investigation alongside our own internal review into the network fault.
“SSEN takes its responsibility to public safety seriously.
“We are aware of reports of minor injuries and damage caused by the incident at Sutton Courtenay and are working with the police and other agencies to identify those impacted.
“We would ask anyone affected to contact us through the power cut helpline 105 so we can investigate further.”
Brown and Mason, which carried out Sunday’s demolition, referred inquiries to RWE.
RWE said: “The three cooling towers at Didcot A Power Station are down. We have received the SSE statement on the power cut and we will look at this very carefully and further investigate what has exactly happened.”
Didcot A stopped operation in 2013 after running for 43 years.
Three of its towers were demolished in 2014.