IPL Says Faulty Supply Cable To Blame for Downtown Explosion

Indianapolis Power and Light says damaged electrical cables were to blame for an underground fire near the intersection of North Street and Capitol Avenue Thursday morning. The fire led to an explosion that blew multiple manhole covers and left about 400 customers without service.  

At about 6:50 a.m. Thursday, IPL and the Indianapolis Fire Department responded to reports of smoke coming from a manhole at the intersection. IPL Chief Engineer Mike Holtsclaw says a shorted underground supply cable was to blame for the fire that led to the explosion. 

“When those cables are short circuiting, various gases are created, the main one being carbon monoxide, which it turns out is a very explosive gas,” Holtsclaw says. “And it only takes about 8 pounds per square inch of pressure to lift a manhole cover.”

This is the second IPL-related underground explosion this week. A faulty termination chamber rocked the 400 block of Massachusetts Avenue Monday evening.

IPL Vice President Joe Bentley says the two incidents are unrelated...and that recent winter weather may have led  to Thursday’s explosion, although he couldn’t say for sure.

“Any contaminants that you have like salt that adds to the water, will actually enhance that short circuit from the cables to ground," Bentley says. "So, we’ve had a lot of snow, and that can contribute.”

About 400 customers were without service as of early afternoon, but IPL expected to have half of those customers power restored by the end of the day. The remainder could be without IPL service longer, but the company plans to provide diesel generated power until service is fully restored.