More than 150 electricity substation sites have been the target of illegal fly-tipping this year, with 52 of these cases being reported from Kent, Surrey and Sussex.
Large settees, metal bed frames and even a piano have been found at power sites.
The incidents can put power supplies at risk by delaying access to vital equipment and endangering staff visiting the sites to carry out inspections.
Cleaning up the rubbish has already cost UK Power Networks several thousand pounds this year.
People are being urged to ring UK Power Networks if they see rubbish blocking a substation so the waste can be safely removed.