Hello,
I have seen various documents on electrical and electronical symbols
on the Ieeexplore site[1]. There you can find IEEE and some IEEE
standards. There are US standards, but most symbols are identical or
very similar symbols as used in many European countries.
Among the documents, there is
- One from 1986 called " Supplement to Graphic Symbols for
Electrical and Electronics Diagrams" ;
- One from 1972, called "American National Standard Graphic Symbols
for Electrical Wiring and Layout Diagrams Used in Architecture and
Building Construction ;
Both documents state: "The individual symbols contained in this
standard may be copied, reproduced, or employed in any fashion without
permission of the IEEE. Any statement that the symbols used are in
conformance with this standard shall be on the user’s own
responsibility."
However, there is a more interesting document called "Graphic Symbols
for Electrical and
Electronics Diagrams" but that does not contain such statement about copying.
If I have more time/motivation, I will try to have a deeper look and
compare with QET.
Hope it helps,
Regards,
Youssef
[1] http://ieeexplore.ieee.org/Xplore/guesthome.jsp