I'm also from a telecoms/electronics background. While there are some things in heavy-duty wiring which might be new to you, your grounding ('scuse the pun ) in basic theory will go a long way.
The physical aspect I dislike the most is probably the crawling through filthy old attics full of fiberglass insulation, a hundred years worth of accumulated dust and debris, and who-knows-what-else (there are a lot of very old houses here in England!).