JACKSONVILLE, Fla. -

JEA released a report Monday that details what happened when an underground fire caused a large power outage last month in Riverside.

They are still trying to figure out the exact cause of the fire that broke out the morning of April 23.

DOCUMENT: JEA's Riverside power outage report

According to the report, a backfeed on a circuit at a JEA substation downtown, along with a fuse pulled by a technician on another downtown substation combined to create an overvoltage situation miles away in an underground transformer in Riverside.

That surge started the fire in the manhole on Riverside Avenue, which then caused a major power outage and businesses to shut down for a good part of the day. Some of those included the Florida Times-Union, the YMCA, EverBank and CSX.

JEA is trying to find ways to keep this from happening again, replacing equipment that is more than 30 years old, and adding warning detectors when surge conditions are building.

The report will be discussed in much more detail at JEA's board meeting at 1 p.m. Tuesday.

You can watch the meeting live online on the JEA website.