DougB posted:I disagree on the comment on the three pole plug, I use a power strip and when I put the three conductor on the transformer I check the power side is the same location on the transformers...
There is no problem with using a three pronged grounding plug for the way you are using it. The problem comes up when the grounding plug wire is connected to a metal part of the transformer - a big no-no. Just cut it and leave it not touching anything.