More than 100 homes around Stroud and Gloucester have been without electricity since Christmas Day.
Initially 900 homes were affected. Generators are being brought in to help the 137 still experiencing problems.
Central Networks, electricity firm E.On's distribution business, said the problem with an overhead cable started early on Christmas morning.
A spokesman said: "There will be compensation for this, but the priority for us is to get them back on."
He said: "We've got 137 customers who've been off for over 24 hours now and we would really like to apologise to them.
"A power cut at any time is annoying and over the festive period like this it's just devastating and we really do feel for them.
"We are pulling out all the stops. We are getting six generators over to them and we will get those connected during the course of the day."
The spokesman said it could take an hour and a half to set up each generator.