Connecting a grounded socket is a prerequisite for the safe operation of powerful electricity consumers. To date, such devices are part of any home electrical wiring and can be installed by yourself. That is why when carrying out repairs in an apartment, it is important to know how to connect a grounded outlet.
Design features
A socket with a grounding contact is a device that is designed for plug-in connection of an electrical consumer to the network. At the same time, the electrical installation housing is connected to the ground loop. Such an additional function is due to the main feature of the design of sockets of this type - the presence of grounding contacts.
It should be noted that in different countries different designs of these electrical products are used. In our country, the most common is type F, which provides for the presence of special metal brackets located in the lower and upper parts of the recess into which the plug of the electrical appliance is inserted.
These contacts are placed in such a way as to ensure their closure before the power circuits. This design allows you to achieve the maximum level of electrical safety even in the event of a breakdown of the insulation on the case. It is important to use these types of connectors in wet areas and near direct contact with water, for example, in the bathroom, toilet and kitchen.
Needless to say, ungrounded outlets are not capable of providing acceptable protection against electric shock.
The principle of operation of protective earthing
In order to correctly understand the purpose and principle of operation of a grounded socket, you should consider in more detail the diagram of its connection diagram.
The installation of sockets with grounding allows you to connect the metal case of the electrical installation with the ground loop. Under normal operating conditions, such a connection does not affect the operation of the electrical network elements in any way, its performance remains the same as when using an ungrounded socket. However, if the insulation is damaged, grounding ensures that there is no high potential on the case relative to ground. It also prevents the buildup of static electricity. This is achieved due to the presence of a wired connection with low active resistance between the metal parts of the case and the ground. In this case, when a person touches a grounded electrical installation, electric shock will not occur, since the resistance of the skin is many times higher than the resistance of the ground loop.
Disadvantages of the ground circuit
Despite the obvious advantages that a grounded socket has, its use still has certain disadvantages:
- Lack of monitoring of the state of insulation and automatic power off in case of violation of its integrity. This drawback fully applies to electrical networks using sockets without grounding.
- The flow of differential current (leakage current) leads to a gradual destruction of the insulation at the point of its damage. When using a socket without grounding, there is usually no question of any leakage current. High potential immediately appears on the body.
- Residual current can lead to heating of the junctions of the ground wires and, as a result, to an increase in their resistance and even fires.
- Relatively high price. The only quality in which sockets without grounding are in a better position. However, the difference in price is insignificant.
All these shortcomings clearly indicate that, in addition to sockets with grounding contacts, devices should be used in the electrical wiring of modern apartments to ensure additional consumer safety. Such devices include RCD and differential automata, allowing you to instantly turn off the section of the electrical circuit in which the leakage current exceeds the allowable values.
Connection rules
Currently, in the construction of housing, an electrical wiring scheme is widely used, which involves the use of a three-wire electrical network. Such a network uses, in addition to phase and zero, also a ground wire.
A common mistake made when installing grounded outlets is to attach a grounding contact to the zero terminal of the outlet.
Zeroing is one of the technical means of ensuring electrical safety, the principle of its operation is to ensure operation when the phase wire is closed to the housing circuit breakers. However, in the event of a break in the neutral wire or an erroneous change in the positions of the phase and zero in the junction box, a situation may arise when phase voltage appears on the body of the electrical installation.
If a two-wire wire and sockets without grounding were used for the installation of electrical wiring in the apartment, then to ensure safety, it is necessary to connect a grounding conductor to each of them or completely change the wiring to a three-wire one.
Since this task in most cases is associated with large-scale repair work and is often impossible, it is advisable to use grounding only for the most powerful consumers, such as electric stoves, washing machines, dishwashers, boilers, underfloor heating systems, etc.
All these devices cannot be connected through sockets without grounding, they require the laying of separate lines connected directly to the electrical panel. In apartment buildings, the ground wire is usually connected to the switchboard housing.
An outdoor socket with a ground is installed in the same way as a socket without a ground. The main difference is that one of the conductors of the three-wire line (which is colored green with a yellow stripe) is connected to the ground terminal.
Swapping the green and blue wires is strictly prohibited, as well as duplicating the connection of the blue wire to ground.
To control the operation of the device, you can use an ordinary electrical tester, which should show a voltage of 220 V between the ground and phase conductors. When these conductors are shorted to each other, the RCD should immediately work.
Thus, having a clear idea of \u200b\u200bhow to connect a grounded outlet, it is quite possible to independently install these critical elements of home electrical wiring.
