A faulty piece of equipment charged with 138,000 volts of electricity erupted into an “electrical arc flash” that cast an eerie blue glow over the skies of New York, Con Edison officials said Friday morning.

The rare phenomenon blew up at the Astoria East Substation on 20th Avenue and 32nd Street around 9:10 p.m. and could be seen across Queens, Manhattan and Brooklyn.

“It’s like a thunder-and-lightning event,” explained Con Ed spokesman Bob McGee. “The loud bangs people heard were likely related to the arc striking the ground grid on the substation from a piece of equipment that’s 20 feet up in the air and carrying 138,000 volts.”

An electrical arc occurs when an electric current flows between two points and produces plasma, which causes visible light.

“You have an arc that’s a lot like a bolt of lightning going from that piece of equipment to the ground,” said McGee.

The stunning event caused power outages at LaGuardia Airport, which was forced to temporarily suspend outgoing flights, and disruptions to 7 train service.

Eric Phillips, a spokesman for Mayor Bill de Blasio, said there were also reports of steam pressure disruption.

“Most of that capacity is already back. The rest will return by midday,” he tweeted on Friday.

The malfunction caused a transmission dip — about a 7 percent drop in the supply of electricity — for about a minute, which kicked some backup systems into gear, McGee said.

Many residents who were home at the time experienced flickering lights.

Despite earlier reports, McGee said there was no actual fire at the substation.

“The illumination was caused just by the arc flash. Once the electrical source removed, the arc flash subsided,” he said.

Con Ed officials are investigating the incident and whether the flash of light was extinguished because the machinery automatically switched off or because it was burned through.

“The affected equipment was isolated to a single section within the substation,” the utility company said in a statement. “Con Edison has restored all major transmission lines associated with this event and is in the process of investigating the root cause of the failure.”

One person was working Thursday night at the Astoria substation but no injuries were reported.

The bluish light sent New Yorkers into a frenzy, with residents posting incredible photos of the event and wondering whether a visit from extraterrestrials was in the works.