One more thought
When I went to electrical school, way way long ago, the knot was explained this way to us. The knot purpose was to stop lightning from following the wire into the structure. Lightning surge is so fast that the surge will not follow the tight curves of the knot. As the current hits the curve it will leave the wire and head to the closest ground. I haven't seen those knots for many years. In the 60's, after electrical storms, I saw a few that had the insolation blown off the knot and a large arc mark on the outside of the fuse panel box, the fuse was not blown and no damage to inside electrical equipment. As electronic protection advanced the knots faded away.........Anyway thats the way I heard it, and saw it, and I'll spend the money on good quality protection, as in most things you get what you pay for!.........and a lot of good karma will also help in an electrical storm, expecially in the Colorado Rocky Mountains !!!
1999 F 150 4X4 5.4L, Auto, 4.56 Gears
2006 23B EXP
Yamaha Inverter Gen.