Transformer or underground vault explosion leaves at least 6,500 without power in Valley Glen, Los Angeles
July 2021Published 29 Oct 2026Responsible editor: Chief Editor
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Companies named in the reporting of this entry (being named is not a finding of fault): Los Angeles Department of Water and Power
What happened
On a Monday morning in July 2021, an explosion at a power transformer or underground electrical vault near Valley Glen, Los Angeles, caused multiple power outages. Residents in Sherman Oaks, Valley Glen, North Hollywood and nearby communities reported losing power, and at least 6,500 residents were affected. The Los Angeles Department of Water and Power had no estimate of when power would be restored. The Los Angeles Fire Department reported no fire, although some smoke was reported in the area, and overhead footage showed that one manhole cover had blown off. The LAFD also reported numerous stuck elevator calls, which are typically related to power outages.
Contributing factors
The source does not state the cause of the explosion, the equipment involved or the time power was restored.
Lessons learned
- Underground vaults and transformers need regular inspection and monitoring for gas build-up and electrical faults so that hazards are found before a failure.
- Utilities should set exclusion zones around vaults and manholes and be able to isolate affected circuits quickly after an explosion.
- Operators should give customers and emergency services timely restoration estimates and warn about building risks such as stuck lifts during outages.
More lessons on detection and monitoring, electrical protection and isolation, outages, backup supply and restoration, from every incident on the register.
Source
Published 2026-10-29. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
