A large transformer fire broke out at a CenterPoint Energy substation in northwest Harris County Tuesday evening.

The fire left thousands without power for several hours overnight, but as of 4:30 a.m. Wednesday only about 100 customers were reportedly in the dark.

Cypress-Fairbanks ISD has announced classes will be held as normal, but parents and students should be careful as some intersections could have flashing lights.

CenterPoint has asked residents to set their A/Cs a little warmer through the day and evening Wednesday, at 78 degrees, to help with the repair efforts and alleviate strain on the grid.

The Harris County Sheriff’s Office was called out to a transformer fire and explosion around 5 p.m. Tuesday at Grant and Kluge roads. Officials say a transformer blew behind Hamilton Middle School. There were no reports of injuries.

Initially, about 75,000 customers were affected by the transformer fire.

Tomball Volunteer Fire Department officials issued a shelter in place for the neighborhoods near the fire, especially to the north as a precaution. The shelter in place has been lifted.