First, what is a US standard? I see so many variations on symbols it makes my head spin. That said, you could try the Electrigon object:
http://www.archicad.ca/?p=192
This will handle most of your needs although there are still a few week spots that I notice from time to time.
Erich
AC 19 6006 & AC 20
Mac OS 10.11.5
15" Retina MacBook Pro 2.6
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