Peco Energy Co. is reporting an "issue with underground cables" near Lancaster Avenue and Rittenhouse Place in Lower Merion.
Peco workers are on site, and the utility company is assembling more specialized crews to assess the damage. Peco will have to cut off electricity before workers can go underground safely, company spokesman Ben Armstrong said.
"The insulation around the cables could be heating up and causing the manhole to smoke," Armstrong said. "You could be seeing smoke coming from the manhole."
It is unclear right now how many people will be affected by power outages, he said. "We'll have a better understanding later in the afternoon," he said.
No roads have been closed.