I'm not an electrician, but years ago I was taught to put an underwriter's knot at the end of the cord when rewiring a lamp or a plug.
I have an extension cord with broken plugs, so I went to our last independent hardware store here and picked up new plugs made, naturally, in Mexico. I dutifully tied my underwriter's knots, but when I tried to get the cover back on the plug it wouldn't fit; there is no space for the knot. There is a little notch beside the fastening screw so I fed the wire through that. Is the knot no longer required, or are these Mexicans trying to burn down my home?