Self disclosure is the all-important part of this. You telling Exelon about this, upfront, is a sign of your integrity. Integrity is one of, if not THE defining statement, for everything we do. Everything starts there. If you didn't, well I think you can finish that picture.
As far as the timeframe, I think the previous 5 years is what is looked at most. some of the more seasoned members will certainly chime in with more than my "I think" statement.
Remember that this is YOU wanting a job. YOU need to take initiative and do what YOU can to make yourself more marketable. Hopefully YOU take notice of the emphasis.
Good luck and hopefully this helps out, even if it is a small amount.