The electrical segments that are part of Ask This Old house shows sometimes have problems I think. On a recent episode the host showed how to convert an old kerosene lantern to electricity. Fine, except he never mentioned the issue that there is a hot and neutral lead and they need to be connected to the correct terminals on the lamp to meet code and maximize safety.
In another episode he used metal boxes but never mentioned the issue of grounding the boxes.
In another episode he installed a panel in an out building and he didn't mention an earth ground connection to the panel. I believe that in addition to the ground wire that comes from the main panel an earth ground connected to a grounding rod or other allowed grounding technique is required. I'm not an electrician but the book I have on electrical codes seems to suggest that this is the case.
Overall the ATOH electrical segments are often seriously incomplete IMO. It is possible that the problem is caused by the producers that want to restrict the amount of time available for the segment. If that is the case they should consider not doing the segments at all if there is inadequate time available to cover critical issues. It is also possible that the problem is with the host. Perhaps he is not thinking enough about which issues are important if somebody is trying to learn how to do something based on his instructions.