WASHINGTON >> The Washington Monument’s lights are back on after going out for the second time in a week.

National Park Service spokesman Mike Litterst said in an email that power went out at the marble and granite obelisk about 5:30 p.m. Monday. He says power was restored after 7 p.m.

Unlike last week’s outage, Monday’s outage included the red aviation warning lights on top of the 555-foot-tall structure.

Litterst says electricians traced the outage to a ground fault. Further investigation will continue Tuesday.

The lights went out on the monument about 7 p.m. Jan. 3; officials said the lights were on when electricians arrived the next morning. The outage was blamed on the monument’s automated lighting system being out of sync.