Symbol 5011 from IEC 60417 - Title/Meaning: ""ON""/""OFF"" (push button) Function/description: To indicate connection to the mains, at least for mains switches or their positions, and all those cases where safety is involved. ""OFF"" is a stable position, whilst the ""ON"" position only remains during the time the button is depressed.
Additional information: 
Published in: First edition, 1973
Own work using: iso.org/obp/graphics/grs/51d118aa-ce12-4d81-aa63-5eb8ec10a8af 200.png
Vectorization:  Mrmw