Mylar balloons are the reason 4,600 PG&E customers in the Diamond Heights neighborhood were without power Thursday afternoon, according to the utility company spokesman.

PG&E spokesman Joe Molica said the outage began around 3:50 p.m. and affected customers from Harrison Street west to Portola Avenue, between 23rd and 30th streets. Power was restored to all customers around 4:20p.m.

Molica said the culprit is believed to be Mylar balloons which were entangled in power lines around 25th and Sanchez streets.

“These balloons escape, and get in the lines,” Molica said. “If you are going to bring them out, please have them tied to weights.”

This is the second such outage for PGE; a similar balloon caused an outage in the Western Addition neighborhood a little more than a week ago.

akoskey@sfexaminer.com