Zero line means that the voltage on this line is zero, and the middle line means that the potential of this line is in the center of other lines, such as a middle line of three-phase alternating current; the ground line is the line connecting the earth, while the ground line does not mean the line in the current loop; it is a protective line, zero line grounding, neutral line grounding, equipment shell protective grounding and so on. It does not participate in the operation of equipment and does not provide current normally. Loop.
The difference between neutral line and ground line in power frequency and low voltage circuit is briefly described as the difference in structure and principle.
1. Structural differences:
(N): The main line is drawn from the neutral point of the transformer after grounding.
(PE): The main line is drawn from the neutral point of transformer after grounding. According to the standard, the main line is grounded repeatedly every 20-30 meters interval.
2. The difference of principle:
(N): It is mainly used in the working circuit. The voltage generated by the zero line is equal to the resistance multiplied by the current in the working circuit. Because of long distance transmission, the voltage generated by the zero line can not be ignored. As a measure to protect personal safety, it becomes unreliable.
(PE): Not used in working circuit, only as protective wire. Using the absolute "0" voltage of the earth, when leakage occurs in the equipment shell, the current will flow rapidly to the earth. Even if the PE wire has an open circuit, it will flow into the earth from the nearby grounding body. In fact, ground rod wire is not only a kind of protective grounding； ground wire is short for grounding device；earth ground wire
is divided into working grounding and safe grounding,. It can be divided into protective grounding, lightning protection grounding and electromagnetic radiation protection grounding.