Uploaded October 2018 | Updated September 2026, 7 hours ago

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Prior to October 27, 1948; much of the Southern California region's electricity operated at 50 hz rather than the 60 hz alternating current we use today throughout North America.

gizmodo.com/before-1948-las-power-grid-was-incompatible-with-the-r-1683629042

waterandpower.org/museum/Mystery_History_Answers(April_2015).html