Symbol 5222 from IEC 60417 - Title/Meaning: Safety isolating transformer, general Function/description: To identify a safety isolating transformer.
Additional information: 
To indicate a fail-safe function, the letter F may be used adjacent of the symbol.
See also symbols 5221, 5946 and 5947
Published in: Supplement J, 1990;2002-10-07;3C/944/FDIS
Own work using: iso.org/obp/graphics/grs/14ffa01a-5055-4c93-8f13-7f79725c65e0 200.png
Vectorization:  Mrmw