Pifico said:
Neutral conductor.
Where can I find information about strange installations sharing the neutral conductor between two different installations ?
Best Regards
Illegal by most code books these days for loads, but they do actually work and were used many years in the past. Actually, they are used quite often but in a different way...
You can obviously google it, but you can share a neutral between two loads in a single phase 240/120 house panel board for example.
Meaning you can you one single romex and feed two loads like let's say two electrical outlets that both have their own breaker switch and sharing the neurtal from one romex. One wire of the romex (say the black) will hook in a 20 amp single pole breaker, then the other wire of the romex (say the white) will get wired into the 20 amp single pole breaker right beneath it...therefore they are 180 degrees out of phase, or you can say that each load is off of a different bus bar in the panel.
The reason you can theoretically do this is that the currents are litterally out of phase, the sin waves are flipped. Therefore the current through the neutral never exceeds 20 amps do to the "crossing out" effect.
You can see how the black and white wire is confusing. 30 years down the road the next guy comes in and does some rewiring. He doesn't know it is a edison circuit and re-wires it to a new load...except now he has line to line voltage...or 240 volts. Bad things happen when you hook 120 volt devices to 240 volt power supplies. For example, a light will burst, a vacuum cleaner will start on fire, a television will just plain fry...etc.
Actually, come to think of it, the wiring coming from the transformer into your home panel is a edison circuit, but a legal one. They share the neutral, but the bus bars are 180 degrees out of phase. The source is a center tapped secondary from the nearest transformer. The wiring is ussually red and black with the neutral being white.
