I've heard it too. Must be an American thing. You don't hear it often though unless, for example, both people are engineers and the topic somehow comes up.

Nor have I. I've never heard of it.

'EE' may be a term used within university science faculties, but -  in the world at large -  I doubt whether most people would know what it means.

It would appear to be a US specific term. I have known people who studied electrical engineering in the UK and not once did I hear them describe their course as EE or double E. EE is a mobile phone network operator in the UK, that's the only time I've ever seen that abbreviation used for anything.

Perhaps it's a US or field term? My brother says Double E and whenever I say that to people in related fields, they know what I'm talking about.

I have never heard that as well