Jones, of 120 Summer St., was a member of a five-person crew that was removing an old transformer from a pole at the fairgrounds off Cleveland Avenue, said City Light Manager Terry Weaver.
City Administrator Bruce Zimmerman said officials did not know what caused the fall. He said city and the Maryland Occupational Safety and Health Administration officials would investigate.
Jones' injuries were so severe that co-workers at the job site took him to the hospital in a city truck instead of waiting for an ambulance, Wetzel said.
An ambulance was called for a fall at the fairgrounds at 10:08 a.m., but the call was canceled, according to Washington County Fire and Rescue Communications.
A grief counselor was available at the hospital to help the other four City Light workers who were at the Fairgrounds when the accident occurred, as well as other city employees, Zimmerman said.
"It's a true loss for the city and a tragedy for us," Zimmerman said.
The last time a City Light employee died on the job was about 13 years ago when Vance Snook was electrocuted while working on a high-voltage wire, Weaver said.
Jones went to work for the city in 1989 as a laborer in the water department. He began working for City Light in 1994.