My brother came to see me yesterday because he was doing some wiring in his house and had to deal with some old knob and tube wires. I have an old house too and am used to knob and tube. He is used to three line Romex.
I have been doing household wiring since I was twelve and my father wanted a light switch in the garage and one in the house. But there were only two wires from the garage to house and a switch at both ends would have required three wires.
I made it work with an electric relay that made sure the two wires were always hot.
In all honesty I still don’t understand electricity after more than 65 years. I know the U.S. has an earth as ground system but the Scandinavian countries have a wire as ground system. That means that only two wires come to my house from the main line in the neighborhood. At the junction box on the house, the electrician drove an 8 foot copper bar into the ground and made it the ground wire for the house. I also know to connect a ground wire to a cold water pipe when a ground wire is needed. Moreover, I have a sump pump that is turned on by two probes that use the groundwater ground as part of the sensor system.
I was not surprised, one day, when the local electric utility guys dug a hole in the street and pounded in a 40 foot copper pole as a systemic ground.
I also know that the high power lines that come into the neighborhood at the top of the tall poles have an electric field around them that is a few feet in diameter. You can hear it buzz on foggy days. I learned about that in high school physics class; the left hand rule of thumb about the electric and magnetic fields that surround an electric wire.
I also learned that the power of the electric field around the wire diminishes as the square of the distance. So the electric radiation at street level from the high power wires is the same as from the small battery in my pocket flashlight.
I had a hippy neighbor who often claimed that the TV tower about a mile away in direct sight was harming us. So I got a friend with several EMF meters to come to my house and measure. Sure enough there were high frequency measurements outside the house but it didn’t penetrate glass or walls.
The low frequency radiation was found near electric plug outlets in the house but it was trivial.
The last report is about a ten year battle with raccoons who always ate the small fish in my fish pond. Finally I put a metal screen just under the surface of the water for one wire; I put a small open copper wire just above the surface around the perimeter of the pond for the second wire. I put a transformer on the household current so the voltage to the raccoons was only 40v. I also put a tiny light on the line so I would know it was on or off when children and pets were around.
The low voltage kept the raccoons away all night. But they could see that the tiny green light went off at 6am. So that is when they would go and eat the fish.
Electricity for today.