Let's analyze why the zero line and the ground line are connected with a multimeter:
The power supply and grounding system of the office building is basically a TN-S system. To answer this question, we must first understand the TN-S system: the TN-S system is the working neutral line (N) and the protection neutral line (PE). Strictly separated power supply system, when the system is working, the protection neutral line has no current, but the working neutral line has current; the working neutral line is generally used for single-phase load circuits, and can be connected to a leakage protector, but repeated grounding is not allowed to protect the neutral line It is not allowed to disconnect or connect to the leakage protector;
That is to say, after the main switch, the working neutral line (N) and the protection neutral line (PE) must be strictly separated, and no connection is allowed. There is no leakage protector. Although it can be used on the surface, it is very unsafe and is prone to electric shock;
Therefore, it is the problem that the neutral line and the ground line after the actual measurement of the main switch are connected. The neutral line and the ground line after the main switch are separated and are not allowed to be connected.
