Originally Posted by bud16415
I think you might have a high impedance meter and it’s leading you to reading all these phantom voltages. A good general purpose multi-meter with lower impedance should not be reading these. Most people doing home wiring will not be testing transistors and such.
A low input impedance meter, like 1000 ohms/volt (1 mA full scale reading for the meter movement) will give you very confusing readings.
The low impedance meter needle stays on the same place on the scale because the current is constant no matter what range you're on, so you might see 50v on the 150v scale (0.3 mA) and then 17v on the 50v scale (0.3 mA) and then 5v on the 15v scale (0.3 mA).
It's because the phantom voltage, 120v in series with thousands of ohms of capacitive reactance from the conductors being close together, acts like a current source rather than a voltage source. Readings like above confirm you are not measuring a voltage source.
With a high impedance meter, the readings are more or less constant regardless of the range you're on, but slightly less than 120v.
Wall outlets and batteries act like voltage sources while LED drivers and fluorescent ballasts act like current sources.
BTW, if the wire colors in the OP's setup are not to code there is still a way to figure out where each one goes, either using an ohmmeter or
an extension cord connected to a known good outlet and a test light or meter.