Hopefully you have turned the power off so it makes no difference which you disconnect first.
No !
For wiring in the USA the Neutral conductor is required to be white or gray by the National Electrical Code.
In residential wiring the white wire is neutral on the 120 volt circuits. On a 3way circuit the red is the traveler and the white is neutral. On a 240 volt 3 wire connection the white & black are hot. On a 240 volt 4 wire connection the black and red are hot and the white is neutral.
Question is incorrect. in a 240 Volt single phase circuit, how can you have A phase and B phase?
yes <<>> No, the ground wire is never to be used as a neutral. In this case if you need a 120 volt circuit from the 220 volt circuit a three wire cable (3C #14) must be installed.
A volt can not be connected to a circuit.
A 240-volt circuit typically consists of two hot wires and a ground wire, with no neutral wire. The hot wires each carry 120 volts, while the ground wire is used for safety purposes. In a 240-volt circuit, the hot wires complete a loop by connecting to a load or device that requires the higher voltage to operate.
Yes, to the precision you can measure it. If it isn't you need to check the ground to neutral bonding at main panel and check the wiring in the circuit for loose connections.
Assuming you are using the correct meter with true RMS you most likely have a loose neutral somewhere in the circuit. Try to measure from hot to ground. If this measures 120V then you most likely have a loose neutral somewhere.
Because the white wire on a 120 volt circuit is the neutral wire that is connected to the silver screw on outlets and switches. It is connected to the neutral bar in the service panel.
It depends on the use it is being put to. It is sufficient for a 24 volt circuit. Too much for a 12 volt circuit and too little for a 240 volt circuit.
A map of a circuit is not a volt. A map of a circuit is referred to as a schematics chart. The schematics chart details the path of the circuit, from beginning to end.