More than 800 homes were left without power following a fault in the underground electricity network.
The homes in and around Sussex Square in the east of Brighton were without power for up to half an hour on Monday night.
UK Power Networks (UKPN) apologised for the problem.
A spokesman said: “UKPN engineers worked as quickly and as safely as possible to restore power to just over 800 customers in the Sussex Square area of Brighton after an underground electricity network fault.
“Customers would have seen an interruption just before 9pm and supplies were restored in two stages, with all back on at around 9.30pm.”