Update - to manhole fire. Bottom of post has some previous incidents listed.
A series of explosions in the city's underground utility lines prompted Indianapolis Power & Light Co. to cut power to about 400 Downtown offices and homes Wednesday.
IPL said heavy rains probably contributed to a short circuit that preceded a series of blasts northwest of the city center.
There were no injuries, but the utility shut off electricity for more than four hours in a 12-block area as a precaution against further explosions. The outages included 22 stoplights.
The Minton-Capehart Federal Building, which went dark along with other nearby structures, closed for the day. Police checked other buildings for people who might have been trapped in elevators.
Brian Freije had a frightening ringside seat when the first blast rocked his graphics business at 118 W. North St. about 11:15 a.m.
The explosion flipped a manhole cover 4 feet into the air as Freije watched from his front window. Bright yellow light and acrid smoke poured from the opening.
"It was like -- wow!" he said. "You saw this yellow, toxic stuff coming out."
Half a dozen more explosions shook his Matrix Imaging building as employees screamed.
Ron Talbot, vice president of customer operations for IPL, said the week's heavy rains drenched underground utility vaults, possibly contributing to a series of "low-voltage faults," or short circuits.
Arcing electricity from the faults likely damaged the insulation on some power lines, producing a volatile gas that sparked, then ignited, he said.
Although the faults were at one location, the gas could have seeped via IPL's conduits to other manholes, producing the string of explosions.
Talbot said 393 customers in the area, bounded by Senate Avenue and Delaware, New York and North streets, lost power until 3:45 p.m., when IPL flipped the electricity back on.
The utility said work was continuing in the block where the explosions occurred, the area bounded by Capitol Avenue and Illinois, Michigan and North streets. Ten customers remained without power there Wednesday night. IPL said their service would be restored within 24 hours.
Heavy rains normally don't present a problem with IPL's equipment, which is designed to operate in wet conditions, Talbot said. He said there was no reason to expect any further disruptions during the wet spell.
Residents and businesses, including The Indianapolis Star, made do as best they could during the outage. The newspaper dispersed some of its staff to satellite offices to continue working while others stayed behind, planning how to put out today's editions.
Glenn Berryman, The Star's vice president of information technology, said the newspaper ran its computer systems, Web site and other essential operations with power from a backup generator. That system had fuel for up to 12 hours of use, and the company had an order placed for more fuel if the outage had continued.
The explosions darkened a busy lunch hour at some Downtown restaurants.
"We had a dining room full of people," said Owen "O.B." Brant, owner of the Bourbon Street Distillery, 361 Indiana Ave.
His cash drawers stopped working, so servers calculated lunch tabs by hand.
The kitchen exhaust fan quit, so the place filled with cooking smoke.
"You don't realize how much you depend on electricity until you don't have it," Brant said, waiting for the lights to come back on.
The Indianapolis Fire Department first suspected a natural gas explosion, spokesman Gregg Harris said.
Just before the blasts, a crew from Citizens Gas & Coke Utility arrived in the area to turn on natural gas service to a building. The company's crews checked the area after the blasts and found no gas leaks, spokesman Dan Considine said.
The city's antiquated combined storm-sanitary sewer system apparently had no role in the episode, officials said.
IPL and Margie Smith-Simmons, spokeswoman for the Department of Public Works, said the company's underground utility space is not connected to the storm water system.
The explosions reminded some of an underground transformer fire Downtown less than a week earlier.
Several buildings near the 200 block of East Ohio Street were evacuated Friday morning after a transformer fire. However, that transformer was privately owned, and the two incidents were not related, IPL said.
In other incidents:
• A transformer exploded July 21 under a sidewalk at 500 N. Meridian St., sending smoke and flames into the air in front of the Safeco Insurance building.
• In April 2003, an apparent power transformer failure outside the Minton-Capehart Federal Building, 575 N. Pennsylvania St., sent a fireball into the air.
• In May 2002, a faulty underground power cable caused explosions in the 400 block of Massachusetts Avenue. Flying manhole covers damaged several cars in the area.
http://www.indystar.com/articles/6/207340-6646-009.html
Heavy rains normally don't present a problem with IPL's equipment, which is designed to operate in wet conditions, Talbot said.
Oh, come ON!