Close to 30,000 Nova Scotia Power customers were without electricity during a brief, but widespread power outage on Thursday because the utility’s backup transmission line in Halifax is out of commission while it gets a new coat of paint.

The utility said it won’t have a backup transmission working on the peninsula for another four weeks.

Over the next month workers are scraping the red and white paint off the giant power tower near the MacKay bridge.

It needs to be repainted to meet marine and aviation safety codes.

Nova Scotia Power said it still doesn't know the reason for the failure, but without the additional tower they have no backup plan.

During the 13-minute outage computers failed, cash registers stopped working and Visa machines shut down. Nova Scotia power said it’s sorry for the inconvenience.

"It would have been determined that it was not going to have that kind of an impact," said Nova Scotia Power spokeswoman Neera Ritcey.

"Having said that, there was an issue that arose yesterday and we will certainly be factoring this into our review."