Earth potential is the reference point for all the voltages in a system and is usually expressed as zero volts or ground. Above earth potential is positive voltage relative to that zero point and below earth potential is negative voltage relative to it. Any voltage has to be expressed as a differential in potential between two points; you can't just say the voltage at some point is thus and so without a reference; if you don't state a reference it is implied that that is what the voltage is relative to ground.Reading soares book on grounding and bonding. The books keeps saying something that's confusing me and hopefully you guys can clear it up. The book keeps saying above earth potential or below earth potential . They are referencing a fault in a system and saying that we want to keep the potential the same as the earth. What does this mean? And how does it apply?
Earth potential is the reference point for all the voltages in a system and is usually expressed as zero volts or ground. Above earth potential is positive voltage relative to that zero point and below earth potential is negative voltage relative to it. Any voltage has to be expressed as a differential in potential between two points; you can't just say the voltage at some point is thus and so without a reference; if you don't state a reference it is implied that that is what the voltage is relative to ground.
But voltages are not always referenced to ground. The voltage at the output of a transformer can be undefined relative to ground; in that case the only way you can express voltage on a phase or line is relative to another phase or line.
