My parents recently purchased a mid-1920s house and are doing some work on it as a retirement home. We had an electrician out to the house the other day; upon peering behind one of the outlets, he made an offhand comment about the outlet (and thus, probably all the outlets) using knob-and-tube.
This had not come up on either inspection report (my parents' or the seller's), so we were surprised. We plan on having a few more electricians out to get additional opinions, but we were wondering if there are any telltale signs of knob-and-tube, particularly when looking at an outlet?
Everything in the unfinished basement looks fine based on criteria we found online (e.g., breaker box looks like it has armored cable); we have yet to check the attic. There was a major addition added on the house ~30 years ago, so it's possible something was done to remove it then (if the house ever had it in the first place). We would like to be a bit more knowledgeable on this when talking with other electricians.