GND and Neutral

[Guest jack]

Good afternoon all What is the difference between Neutral wire and ground wire? Aren’t they the same, does a neutral then have voltage in it? Like if I measure the voltage from ground to neutral would I get something other that 0V What I learned in college that neutral is ground but now in electrical drawings I see wire named as neutral and wires named as ground Thanks a lot for your help

[JimRowell]

The neutral wire is grounded but there is a huge difference between it and the ground system. The neutral is designed to actually carry current and to be reliable in doing so. The general ground system is not supposed to carry any current in normal circumstances. The neutral is grounded at one point only and that is at the very beginning of the system meaning right at the transformer it originates from. The one exception to that is if it's from an external system such as your local utility in which case it's re-grounded where it enters the building. It's not connected to ground at any point downstream. The reason it's grounded in the first place is so that should the general "grounding" system become energised by accident (meaning metal enclosures, plumbing, etc), there will be a complete short-circuit path back to the transformer via the general grounding system and the fuse will blow before anyone comes in contact with it. If you allow current to normally use the general grounding system and someone breaks stuff apart, removes a ground wire, etc, they would then get electrocuted. If you measure the voltage from the neutral to ground, you should ideally get 0V. In practice, you will often see as much as 5 volts or more. High voltages between the neutral and ground (roughly above 5) can cause damage to some devices especially electronics. Jim Rowell