Experienced electricians claim that if the shieldgrounding conductors are connected, and sockets and plugs are provided with grounding contacts - you should not worry about anything. Protective earthing and zeroing are necessary to maintain electrical installations against electric shock when the insulation is damaged.
It is worth paying attention to the problem of connectingground wires for water supply and heating pipes. This can not be done in any case! It can entail human sacrifices, and you will easily fall under the article about violation of the rules of electrical safety engineering! Her punishment will be imprisonment.
Many craftsmen practice circuit simulationgrounding. They connect the "zero" protective and working conductors in the euro outlet. This is extremely dangerous! Often, there are cases of burnout in the "working zero" shield. At the same time, 220V is formed on the computer or refrigerator case and other devices. As in the first case, victims can not be avoided, only with the difference that there is no one to bear responsibility, except for the one who made this connection. Most often suffer the owners themselves, saving on the call of a professional electrician.
Grounding and zeroing use, as a rule,as one of the security options. On the housing of the switchboard on each floor there is a zero potential, which passes through the shield, has contact with the body with the help of bolted fastening. Zero conductors of apartments on the floor are also connected to the shield body. Each end is brought to its bolt, here connect the conductor "grounding" or "zeroing", as it is more convenient for you to call it.
Electricity is great, but enougha dangerous force. Despite the fact that it has been described for a long time, counted up, various tables are created, striking in their volumes, the regulatory framework that determines sinusoidal electrical signals at a frequency of 50 Hz, plunges the neophytes into awe and panic. One of the frequent questions is grounding and zeroing. Contradictory opinions on this topic do not give a clear answer. How to establish the truth in this difficult and serious matter in practice? Protective grounding and zeroing require more careful and responsible consideration.
Electrical safety in electrical installationsis divided into: installations that have above 1 kV in a network with effectively earthed or isolated neutral. For the first case, work with high currents is provided, in the second case - with small currents and earth faults. Also there are electrical installations up to 1kV in the network. For them, a grounded and isolated neutral is provided. In most office and residential buildings in Russia, a dull-earthed version is used.
The principle of the scheme is called grounding and zeroing.
If a voltage or phase is applied to thea metal case connected to zero, a short circuit occurs in the network. At this moment, the current increases to enormous values. This causes instantaneous triggering of devices responsible for safety and protection. They are fuses, circuit breakers. They will timely disconnect the line that feeds the damaged device. In any case, there is a time limit for the automatic fire alarm to automatically turn off the faulty line.
Zeroing and grounding are carried out by specialconductors provided for such cases. In single-phase wiring, this can be a third core of the cable or wire. In order for the protection device to switch off at the intended time, the phase-zero resistance in the loop must be small. For zeroing and grounding to be effective, very stringent quality requirements apply to the installation of the network and connections. In addition to quickly disconnecting power from the damaged line, the neutral is grounded, and zeroing in this case guarantees a low voltage. When a person touches the body of an electrical appliance, the probability of his electric shock is completely excluded. With a grounded neutral, zeroing is a specific type of grounding.
