...Or neither. Two of the best designers I know -- working at a very high level, internationally -- don't know the basic of electricity, and y'know what? The audience doesn't care.
When I tell students that I will be docking them for errors in spelling and grammar, I'm usually greeted with cries of, "...But this isn't English class!", as if the purpose of English class were to teach people to use correct English...in English class.