He rags on about contractors not getting licenses or permits, and hiring non-qualified people, then in the next scene he's installing wiring.
Having not watched Holmes in a few years the episodes you refer to have been missed. I do not recall any wiring being done by Mike Holmes. I do recall him pointing out some of the problems with wiring in homes. Mostly it was hidden junction boxes or bad wiring. In the episodes in my recollection he always had a qualified contractor doing the electrical work.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)