Shield for automatic machines and electric meter: construction, installation, box assembly and connection of electrical elements
The cycle of electrical work in the room ends with the installation of a switchboard. To do this, you can buy a module in the retail network (boxing) for the apartment, equipped with a protective shutdown device, circuit breakers (machines) and single-phase meter.
For reasons of economy, the shield can also be assembled with your own hands from individual elements. The place for installation of an electric board is chosen proceeding from economy of expenses of an electric cable and convenience of operation of elements of boxing..
General information about the electrical panel
The electrical switchboard is a box, in which are compactly placed:
- electricity meter (electric meter);
- PZV (safety shut-off device);
- automatic wiring protection.
Depending on the type of material and method of installation, electrical panels are:
- with plastic or metal housing;
- overhead or built-in.
Product body
Electric shields with plastic or metal body are available. Moreover, the plastic material has high resistance to high temperatures, which is of great importance for fire safety. Models made of this material have a stylish look, so they easily fit into any interior.
There are many modifications of the metal shield and, if necessary, it is easy to choose a box with the right equipment.
Box type
Depending on the type of electrical box in the room using switchboards of two types:
- built-in, which experts recommend for hidden wiring;
- overhead - installed in rooms with external electrical wiring. For fastening of such board use self-tapping screws or a dowel nail.
The built-in guard differs in the compact size and attractive appearance. According to the recommendations of experts, its installation is carried out in a specially equipped niche made of alabaster and gypsum.
Elements of the electrical panel and their purpose
Buying an electric panel of a standard complete set, you get along with it:
- electric meter (if necessary);
- differential automata (UZO);
- introductory machine;
- automatic switches;
- two tires (zero and ground).
Assignment of elements.
- There is a DIN-rail for fastening of automatic protection devices on a board. This special device is made of metal plate and mounted on the body of the shield. With a regular metal hacksaw, the DIN rail can be easily cut to size.
- The electric meter is mounted for accounting of the consumed electric energy.
- Circuit breakers are designed to protect wiring. Before installing them, you need to find out what power is connected to the mains, and then pick up the number and face value of the machines.
- The distribution bus is required to connect all neutral wires to the shield (workers). A second busbar is provided to connect the ground wires. The tires can be closed or open. Closed version is safer, as it eliminates contact with the busbar.
- ELV - protective tripping device, which is sometimes called a device to protect human life from electric shock. It is for this purpose that it is installed.
- Electrical wires of the required cross-section are used to make connections.
Assembling the electrical panel
Once the shield is mounted on the wall, you can start assembling it. It is very important to follow the rule: for a single-phase network it is necessary to install a two-pole input circuit breaker and a three-pole one for a three-phase network.
The order of compilation
The required number of electrical cable ends is connected to the switchboard. Preferably, so that they are signed in advance, otherwise you will have to "ring" each wire (to correctly identify them by purpose), and spend extra time on it.
Further, the following steps are required.
- The end of each wire is released from the top layer of insulation. If they have the same color, then be sure to indicate the core phase.
- By means of self-tapping screws to a board fasten a mounting DIN-rail for installation on it of automatic machines of protection. Their connection is performed using special latching devices. To do this, tighten the latch on one side of the protection device with a narrow screwdriver, then put the machine to the rail and close. So, make installation of each of the provided automatic machines of protection. At the same time they need to be arranged in the following order:
- the entrance automatic machine is mounted on the right;
- next after the input machine install the ELV (safety shut-off device);
- installation of other automatic machines is carried out according to convenience of operation.
Connection of electrical elements, installed in the shield
Once all the components have been installed in the electrical panel, the connections are made.
-
Zero cores are connected to the DIN rail, which must be fitted lengthwise. Exceptions are groups, connected via RCD.
- Connecting machines. For this purpose the entrance to the top terminals of the automatic machine is brought (food), and to the lower ones connect the output - load (wires of phases of power supply of electric groups indoors). If it is necessary to replace or connect additional wires, the consumer will know exactly which contacts are fed and loaded.
- In addition to the automatic protection in the box install a differential automatic (UZO). Groups of electric wires are connected to this automatic machine, which are located in places with high humidity.
The order of installation of the electric meter
Before connecting the electricity meter, be sure to specify the procedure for connecting the appliance to the mains. It's about that, that power supply controllers can give permission for independent connection of the electric meter. If you do not receive such permission, then you will need to bring the wires to the meter, then the controller makes the connection and seals it.
It is not superfluous to remind about the need to install in front of the electric meter of the protective switching device - bipolar circuit breaker. The machine performs the following functions:
- protects the meter from short circuit and fire, and also provides preventive or repair work;
- limits the allowable power. It will be regulated by the value of the machine.
There are a few simple steps you can take to install the meter directly.
- To attach the meter to the shield you need to use a latch, located behind him, and install the device on the DIN rail.
- Install waste unipolar machines (for an apartment it is enough to have two).
Installation of the electric meter is made at height from 0,8 to 1,7 meters from the floor, convenient for taking readings of consumed electricity. In apartments basically establish electric meters in the following execution:
- mechanical;
- electronic.
The way they are included is direct, wiring diagrams of electronic or mechanical electricity meters are the same.
RCD - protection against electric shock
Man lives surrounded by electrical appliances, many of them have a metal body, which is a conductor of current. For various reasons, but more often when the insulation is broken, there is a short circuit of wires on the case of the electric device.
In the absence of grounding, accidental contact with the device can be dangerous to health, perhaps, even human life. To avoid accidents, associated with electric shock, must be purchased and installed in the apartment / house - ELV.
ELV - protective tripping device is installed on the electrical panel for that, in order to:
- protect a person from electric shock;
- prevent flash due to leakage current in the electrical wire.
How RCD works?
Externally, the device is a module, with the split mechanism established in it and the differential transformer. To check the operating status, click on the "Test" button and the ELV should work.
The principle of operation of the device is to control the amount of current, which in a closed circuit must be the same (at any point). In that case, when the insulation in the connected appliance has been damaged and a phase appears on the housing (potential), equal to the mains voltage, The RCD will react instantly by turning off the power supply.
Another example, when you can accidentally touch the phase wire and at the same time to the conductive, but the grounded housing of the device, example, touch the heating radiator when vacuuming. The value of the current in the phase wire, will be more, than in zero, exactly the same amount, which will pass through the human body. RCD will note this difference and there will be a protective power outage.
Unfortunately, if there is a simultaneous contact with the neutral and wire phases, then the ELV does not protect against such accidents. For electrical wiring in apartments, experts recommend choosing ELVs with parameters:
- operating current 32 A;
- leakage current 30 ma.
Automatic wiring protection
The circuit breaker is installed to protect the electrical wiring from damage. Choose such a machine, focusing on the cross section of the wire, depending on the magnitude of the maximum current, consumed by electrical appliances. Fuses are a direct protection of the devices themselves, installed in them.
Circuit breaker functions
The machine is designed to perform two protective functions:
- instantaneous current jump, exceeding several times the nominal value;
- slow thermal protection. It will work, if the rated load current is slightly exceeded in the range of 15 to 60 minutes.
Instant current jump
The first option of protection will work at short circuit in electric wiring or in the device, which is connected to the mains. In this case, the current may matter 100 A and in the absence of automatic shutdown, the insulation would first be completely melted, and then wires. So, electrical wiring would be completely unusable.
Slow thermal protection
In order to eliminate false positives of the machine, the option of slow thermal protection is provided. If for a short period of time the current, passing through the machine (with face value in 25 A), will matter 30 A, then due to the inertia of thermal protection, the circuit breaker will not work.
Example, inclusion of the vacuum cleaner in a network, loaded with current in 15 A, will give her his 10 A plus will 5 A on the start of the engine. The result is a short period of time the machine, designed for 25 A, passes current through itself 30 A without disconnecting the power supply.
How to choose the right circuit breaker?
When choosing a machine to protect household electrical wiring, the reference point is only the cross section of the wire. In general, you can buy a vending machine in the retail network, designed for such protection currents (in accordance with the standard): 1, 2, 3, 6, 10, 16, 20, 25, 32, 40, 50, 63. The specifically required denomination of the automatic switch-off is set using a special table. In addition to protection current, the machine must be suitable for use in an AC mains with a voltage value 220 volts at frequency 50 Hz, with the characteristic of shutdown on type With and a class 3.
When choosing circuit breakers for all these characteristics, desirable, obtain appropriate explanations from experienced professionals, providing services for the installation of electrical equipment.
It should be noted, that the choice of machine will be correct provided, when the cross-section of the wiring is also taken into account, corresponding to the meter from the outside. Example, if after repair in the apartment the wiring with a section to is carried out 2,5 mm2, and from the shield, installed in the entrance, routed cable, section of which 1,5 mm2, then you need to buy a machine, focusing on a smaller wire cross section. You can also replace the wires, approaching the meter from the electrical panel in the entrance, on large cross-section lived.
Works, related to the assembly and installation of the electrical panel, meters or circuit breakers, can be performed independently, not forgetting to adhere to PEU (rules of arrangement of electrical installations). However, in practice you can face many nuances of the workflow, which in detail is known only to specialists, working in the field of electrical networks.
