The role of equipotential is to prevent electric shock injury due to the potential difference over the safety voltage.
Equipotential: that is, two or more points of the voltage is equal, only the voltage is equal to have the possibility of connection, otherwise they have to pass through the middle of the resistance or capacitance and some other components to make them become equal to be connected.
The equipotential connection is to separate the devices that conductive objects with equipotential connection conductor or surge protector connected to reduce the lightning current in the potential difference between them.
In the international and our country are stipulated, the power supply into the outdoor should be implemented "total equipotential connection", that is, the power supply into the house line outside the vicinity of all the metal components, piping are connected to the PE line.
In the particularly humid, high risk of electric shock places must also implement the "auxiliary equipotential connection" that is, all the metal components in the place, piping and then PE lines connected to each other. The purpose of equipotential connection is to make all metal construction in the PE line at the same potential, in order to reduce the contact voltage, improve the safety of electricity level.
Expanded Information:
Total Equipotential Connections p>The total equipotential connection is not the same for different grounding systems, for the commonly used TN system, its role is as follows:
1, when a ground fault occurs in the building, it can reduce the resulting contact voltage.
2, when a ground fault occurs in the power line outside the building, it can eliminate the potential difference formed inside the building by the ground voltage introduced through the PEN conductor (or PE conductor).
3, to eliminate the potential difference generated by the dangerous potential conducted through the metal pipeline, lightning current through the flashover generated by the high potential counterattack.
Total equipotential bonding (MEB): total equipotential bonding in the whole building, it can reduce the degree of indirect contact within the building electric shock contact voltage and the potential difference between different metal parts, and eliminate the building from outside the introduction of dangerous fault voltages through the electrical wiring and metal piping hazard.
It should connect the following conductive parts to each other through the grounding busbar (total equipotential bonding terminal block) near the incoming distribution box:
-- PE (PEN) busbar of the incoming distribution box;
-- metal pipes of the utilities, such as the electrical lines and various metal pipes. Metallic piping for utilities, such as water, sewer, heat, and gas piping;
--Metallic structure of the building;
--If an artificial ground is provided, it also includes its grounding electrode lead.
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