Recently & more than once, we have been asked
the question “can a standard step down dry type
transformer (<600V) be reverse connected in lieu
of using a step up transformer. For example, can
a 480V, 3Ø Δ to 208Y/120V, 3Ø transformer be
connected as a 208Y/120V, 3Ø primary to 480V, 3Ø
Δ secondary”. We have researched this issue &
have provided the following links & pdf file to
help educate us all. The pdf file has bookmarks,
& includes excerpts from the NEC, IEEE, Square D
& ACME. This file & these links are
not necessarily our opinion, but are offered as
educational material only. We have also embedded
a link to a very informative website regarding
transformers, which also links to many other
transformer sites. Also, we submitted this
question to Mike Holt’s forum, & have embedded
links to these forums. We have found this issue
to be quite interesting, & we hope you enjoy.
