Hi, I'd like to build my first Benchtop Power Supply Unit and I'm looking at the parts I'd need. I went trough some datasheets and now I am asking myself a question. If you look at this datasheet: http://www.hammondmfg.com/pdf/5c0018-19.pdf you can see that every transformer have a 115/117V required at the primary (nominal). Why 115/117V? Historical reasons? In Canada we have a 120V/60Hz and my outlets give me 120V. I'd run my circuits with a 1.03/1.04 pu. Any idea why?