A three-phase socket is designed to connect consumers of electrical energy to a 380 volt network. It should be noted that three-phase sockets are also actively used to connect powerful single-phase consumers, for example, stoves or hobs. Most of these electrical appliances are capable of operating on 380 or 220 volts, both of which use a three-phase connector. The only difference is in the wiring diagram.
Design
Since the connection of consumers to a 380 volt network involves the use of three phase wires (L1, L2, L3), as well as neutral (N) and protective (PE) wires, the design of a three-phase connector differs significantly from two-pole devices designed to connect single-phase consumers.
It should be noted that the terms "three-phase" and "three-pole" are not synonymous. Each pole of the device represents an independent path for the passage of electrical current. Therefore, an ordinary two-pole 220V socket equipped with a grounding contact is a three-pole one.
The main components of a power outlet designed for a voltage of 380 volts are:
- Body base.
- Protective cover.
- Mechanism.
- Sealing ring.
Currently, electrical three-phase connectors with four or five pins of a needle or knife type are used. The choice of one or another model of such equipment is carried out based on the characteristics of the connected consumer.
A three-core wire can be used to connect three-phase electric motors to a 380V network, as well as other symmetrical loads. To connect consumers that create an unbalanced load, a five-pin socket is used, equipped with a zero and ground contact.
There are also 380 volt devices with 7 connectors (each phase has its own zero, as well as a common ground conductor), such devices are used in rooms where it is necessary to ensure a very high level of electrical safety.
Minor changes in the design of three-phase sockets can be made based on their power, purpose, as well as the degree of protection against dust and moisture. There are sockets with protective shutters, 380 volt inclined, devices equipped with a plug, flat, waterproof, etc.
Mounting order
The basic rules to be observed when installing such a device remain the same as when installing a two-pole socket designed to operate on a 220 volt network.
The procedure for this may be as follows:
- Before performing any work on the wiring, turn off the voltage at the introductory electrical panel.
- To connect suitable wires from a 380V network to a power outlet, it must be disassembled. To do this, unscrew the bolts located on the front of the product case and remove its cover.
- The base is fixed to the wall. In order to achieve an even location of the device body, you should use the building level. The mounting method depends on the material of the wall on which the socket is installed.
- The power supply cable is being inserted into the base of the device. In the case of open laying of such a cable, it must be enclosed in a corrugated tube. For hidden laying, you must first perform wall chasing. Any work with elements of the electrical network with a voltage of 380 volts can only be carried out with the power off.Before inserting the cable into the socket, a sealing ring is put on the corrugated tube, which is inserted into the corresponding grooves located on the base of the housing.
- The insulation is removed from each core of the power cable at a distance of 10 mm from its end.
- The power cable cores are connected to the socket terminals. For some electrical consumers, an important condition for normal operation is the correct phase sequence. This means that you should carefully monitor the correct connection of the phase wires to the socket contacts. The PE core insulation is yellow with a green stripe. Most models of three-phase sockets have markings on their bodies that allow you to unambiguously determine which connector you need to connect one or another wire to. Phases are indicated by the symbols L1 (white wire insulation), L2 (black or black and white), L3 (blue).
Advice! If the electric motor is connected incorrectly, when the voltage is applied, it will begin to rotate in the opposite direction. To eliminate this malfunction, it is enough to swap two adjacent phases in the outlet.
- The protective cover is installed.
- The correct functioning of the device is checked by connecting a consumer to it and applying voltage.
Choice of a three-phase socket
Before buying a 380V socket, you should clearly define what technical and operational characteristics it must meet.
The main parameters of 380 volt devices are:
- Rated current. The value of this parameter is determined based on the total power of consumers connected to the device. The standard values of rated currents for 380V sockets are: 16, 32, and also 64 A.
Important! When connecting three-phase consumers of the same power to a 380V network according to the "star" or "triangle" scheme, the currents flowing through them will be different. This should be taken into account when choosing an outlet, as well as the cross section of the connecting wires.
- The phase current flowing in the electrical circuit when the consumer is connected to the 380V network according to the “star” scheme (the most common connection method) is equal to:
where cosφ is the power factor determined by the properties of the consumer.
- Number and type of contacts. To date, many consumers connected to a three-phase 380 volt network are supplied without an electrical plug. However, in some cases it is necessary to select an outlet for an existing plug.
- The degree of protection of the device case from dust and moisture (IP). This parameter is extremely important for products installed outdoors or in rooms with high humidity. In these cases, it is best to use devices that have a degree of protection not lower than IP44.
- To connect portable electrical equipment, pay attention to three-phase cable sockets in a mobile version.
Installing a three-phase outlet in a 380V network is not too different from installing a single-phase two-pole device and can be done even by a non-specialist. However, to ensure the correct operation of consumers, you should pay increased attention to the wiring diagram in these devices. In addition, any work on the installation or repair of electrical equipment should only be carried out with the power turned off. Voltage 380V is life-threatening, therefore, before performing any actions with electrical wiring elements, be sure to make sure that it is not present.
