Alarm shell grounding protection and zero connection protection are collectively referred to as protective grounding

The alarm shell grounding protection and zero connection protection are collectively referred to as protective grounding, which is an important technical measure taken to prevent personal electric shock accidents and ensure the normal operation of electrical equipment.

The differences between the two types of protection are mainly manifested in three aspects: First, the protection principles are different. The basic principle of grounding protection is to limit the leakage current of the leakage equipment to the ground so that it does not exceed a certain safety range. Once it exceeds a certain setting value, the protector can automatically cut off the power; the principle of zero protection is to use the zero line to make When the equipment touches the shell and forms a single-phase metallic short circuit after the insulation is damaged, the short-circuit current is used to prompt the protection device on the line to act quickly. Second, the scope of application is different.

The alarm shell grounding protection system has only phase and neutral wires. The three-phase dynamic load does not need a neutral wire. Just ensure that the equipment is well grounded. The neutral wire in the system shall not have any more than the neutral point of the power supply. Ground connection; no matter what the situation of the zero protection system requires, the existence of the protective neutral line must be ensured. If necessary, the protection neutral line can be set up separately from the zero protection line. At the same time, the protection neutral line in the system must have multiple Repeat grounding at the same place.

After understanding the above of the alarm shell, the principle is the same. Let’s talk about your protective grounding and protective grounding. Protective grounding is to connect the equipment shell, power distribution cabinet, instrument automatic control system shielding wire, etc. to the standard The ground wire is connected, not connected to the protection system; protective grounding is to connect the equipment shell, power distribution cabinet, etc. with the neutral wire drawn from the transformer. It should be noted that sometimes the ground wire of the electrical system and the ground wire of the instrument automatic control system must be insulated from each other.