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.
Answer for USA, Canada and countries running a 60 Hz supply service.240 volt two wire circuits loads do not need a neutral to operate. A three wire 240 volt circuit that needs a neutral, will have a neutral the same size as the current carrying conductors. In this case a #10.
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.
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.
If it is a 120/240V receptacle (such as for a dryer), then yes, there are two 120 volt leads and a neutral in the 240 circuit, the adapter is just using one 120 volt lead and the neutral to convert it to a 120 volt circuit.If the circuit is just 240V, then there is no neutral.As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.Before you do any work yourself,on electrical circuits, equipment or appliances,always use a test meter to ensure the circuit is, in fact, de-energized.IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.
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.
what kind of circuit? if it's a subfeed from one panel to another same size as hot wires. if it's a straight 240 volt circuit #8. depends on what kind of circuit.