Residents living in El Cajon were told to stay indoors while firefighters battled a transformer fire early Tuesday.
The fire was sparked around 7:30 a.m. at E. Lexington Avenue and Lincoln Avenue according to firefighters.
Power lines fell on several cars, causing damage to eight vehicles.
During the incident residents were advised to stay indoors along the 100 to 200 blocks of Lincoln Avenue according to City of El Cajon public information officer Monica Zech.
Eventually, residents on the east side of Lincoln Avenue were allowed to leave, but the residents on the west side are still confined to their homes, Zech said in a written statement.
When mylar balloons got caught in overhead power lines, the lines were overloaded, broke and fell on cars parked along Lincoln Avenue according to a utility spokesperson.
As of noon, approximately 950 SDG&E customers were still without power. The utility believes power may be restored by 3 p.m.
No injuries were reported.