Features of the connection of automatic devices and RCD in the panel: schemes + rules for installation
From the proper connection of electrical wiring in the house depends on the comfortable living of all its inhabitants and the smooth operation of household appliances. Do you agree? To protect the equipment in the house from the effects of overvoltage or short circuit, and the inhabitants from the dangers associated with electric current, it is necessary to include protective devices in the circuit.
In this case, it is necessary to fulfill the main requirement - the connection of the RCD and automata in the panel should be done correctly. It is equally important not to be mistaken with the choice of these devices. But do not worry, we will tell you how to do it right.
In this article, we will focus on the parameters by which the RCD is selected. In addition, here you will find features, rules for connecting automata and RCDs, as well as many useful wiring diagrams.And the videos given in the material will help to realize everything in practice, even without the involvement of specialists, if you know a little about electrical engineering.
Basic connection principles
To connect the RCD in the panel need two conductors. According to the first of them, the current goes to the load, and according to the second - it leaves the consumer along the external circuit.
As soon as a current leakage occurs, the difference between its input and output values appears. When the result exceeds a predetermined amount, the RCD triggers in emergency mode, thereby protecting the entire apartment line.
Devices of protective shutdown negatively affect short-circuit (short circuit) and voltage drops, so they themselves need to be covered. The problem is solved by including in the circuit of automata.
The current supplying electrical equipment flows through one of the windings of the core in one direction. It has another orientation in the second winding after passing through them.
Independent installation of protection devices involves the use of circuits.Both modular RCDs and automatic devices for them are installed in the panel.
Before you begin installation, you need to solve the following questions:
- how many RCDs should be installed;
- where they should be in the scheme;
- how to connect so that the RCD works correctly.
The rule of wiring states that all connections in a single-phase network must be included in the connected devices from top to bottom.
Professional electricians explain this by saying that if you start them from below, the efficiency of the vast majority of automata will decrease by a quarter. In addition, the master, working in the shield, will not have to further understand the scheme.
RCDs designed for installation on separate lines and having small nominal values cannot be mounted into a common network. In case of non-observance of this rule, both the probability of leaks and short circuit will increase.
The choice of RCD on the main parameters
All technical nuances associated with the choice of UZO are known only to professional installers. For this reason, experts should make the selection of devices even in the development of the project.
Criterion # 1. The nuances of the selection of apparatus
When choosing a device, the nominal current passing through it in continuous operation is the main criterion.
The value of In is in the range of 6–125 A. The differential current IΔn is the second most important characteristic. This is a fixed value at which the RCD is triggered. When it is selected from the range: 10, 30, 100, 300, 500 mA, 1 And safety requirements have priority.
Affects the choice and purpose of the installation. To ensure the safe operation of one device, they are oriented to the value of the rated current with a small margin. If protection is needed for the house as a whole or for an apartment, all the loads are summarized.
Criterion # 2. Existing RCD types
It is necessary to distinguish between RCD and by type. There are only two of them - electromechanical and electronic. The main working unit of the first is a magnetic circuit with a winding. Its effect is to compare the values of the current going into the network and returning back.
There is such a function in the apparatus of the second type, it only performs its electronic board. It works only in the presence of voltage. Because of this, the electromechanical device protects better.
In a situation where the consumer accidentally touches the phase wire, and the board is de-energized, in the case of installing an electronic RCD, the person will be under voltage. In this case, the protective device does not work, and the electromechanical device in such conditions will remain operational.
Installation of UZO and automatic machines in a guard
The electrical panel, in which the metering and load sharing devices are located, is usually the place for the installation of a RCD. Regardless of the chosen scheme, there are rules that are required when connecting.
Main connection rules
Along with the automatic shutdown device, automatic machines are also installed on the shield. All that is needed for this is a minimum of tools and a competent scheme.
The standard set should consist of:
- from a package of screwdrivers;
- side cutters;
- socket wrenches;
Also for installation you will need a cable of VVG of different colors, selected in the section in accordance with the currents. PVC insulating pipes perform marking of conductors.
When there is a place on the DIN-block available on the shield, a safety device is mounted on it.Otherwise, install additional.
The key principle of installation is as follows: contact of the neutral conductor after the RCD with either the input zero or grounding is unacceptable, therefore it is isolated by analogy with other conductors.
It is necessary to switch on the automatic circuit breaker in series with the RCD. This is also one of the most important rules.
When the protection of the entire housing is performed using a single UZO, use a scheme that includes several machines.
The project includes, in addition to the additional AVs, another component - the zero bus isolator. Mount it on the body of the shield or din-rail.
Introduce this addition because with a large number of neutral conductors connected to the output terminal of the tripping device, they simply do not fit in one clip. An isolated zero tire is the best way out of this situation.
Sometimes electricians, in order to place the entire bundle of neutral wires in the socket, decide on filing the conductors of a single-core cable.In the case when the cable is stranded several veins are removed.
This option is better not to use, because due to the reduction of the cross section of the conductors, the resistance will increase, therefore, the heating will increase.
As the number of mounting holes, and their diameter may be different. The tire of the earth is attached directly to the hull.
Zero wires in one twist - an additional inconvenience in detecting damage on the line, as well as when you need to dismantle one of the cables. It can not do without unscrewing the clamp, uncoiling the harness, which necessarily provokes the appearance of cracks in the veins.
You can not mount simultaneously and two wires in one socket. The inputs of the circuit breakers are connected by jumpers. As the last for professional installation use special connecting tires called "comb".
Features of connection diagrams
The choice of the scheme involves taking into account the characteristics of a particular electrical network. Among the many options there are only two schemes used to connect the machines and the RCD in the panel, which are considered basic.
In the first and simplest way, when a single UZO protects the entire electrical network, there are disadvantages. The main problem is the difficulty in identifying a specific damage site.
Secondly, when some kind of malfunction occurs in the RCD operation, the entire system will be taken out of operation. The safety device is assigned a place immediately after the meter.
The following method provides for the presence of such devices on each individual line. If one of them fails, all the others will be in working condition. To implement this scheme requires a more dimensional shield and high costs in financial terms.
Details about the simple scheme
Consider the connection of RCDs with automata on a simple apartment panel. At the entrance there is an automatic switch bipolar. It is connected to a bipolar RCD, to which two single-pole machines.
The output of each of them is connected to the load. In principle, the RCD is introduced into the circuit as well as an automatic switch.
The phase supplied to the switch-on device enters the input of the RCD with the output on the machines. The zero output from the machine goes to the zero bus, and from there to the entrance to the device.
From its output, the zero conductor is already directed to the second zero bus. In the presence of this second bus is a special nuance, not knowing which it is impossible to achieve the normal functioning of the circuit.
RCD in the process of controlling both incoming and outgoing voltage - how many went into the input, so much should be at the output.
If the balance is disturbed and at the output it is more by the value of the setpoint to which the RCD is set, it is activated and the power is automatically turned off. The zero bus is responsible for this process.
In electrical circuits, where installation of a protective shutdown device is not foreseen, there is only one common zero.
In the circuits with RCD, the picture is different - several such zeros are already present here. When using one device, there are two of them - common and the one relative to which the protective device operates.
If two RCDs are connected, there are three zero busbars.Designated by their indices: N1, N2, N3, etc. In general, there are always one more zeros than residual current devices. One of them is the main one, and all the others are tied directly to the RCD.
If it is intended to connect not all the equipment through the RCD, then zero is supplied from the common bus. The safety device in this case is excluded from the circuit.
When adding a single-pole machine operating from a RCD, from the output of the latter, the phase is fed to the input of the circuit breaker. From the switch output, the conductor is connected to one contact of the load. Zero on it leads to the second conclusion. It arrives from the zero bus created by UZO.
On the shield there is another element - the protective earthing bus. Correct operation of the RCD is impossible without it.
The three-wire network is only in new homes. It always has a zero phase and ground connection. In houses built a long time, there is only a phase and zero. In such conditions, the RCD will also function, but a little differently than in a three-phase network.
As a way out of the ground position, the third conductor is brought to the sockets, and then to the ceiling to the place where the chandeliers are connected. To the switches "ground" is not served.
Connection option for automatic machines without RCD
There are cases when one of the machines needs to be connected, bypassing the protective shutdown device. Power is connected not from the output of the RCD, but from the input to it, i.e. directly from the machine. The phase is fed to the input, and from the output it is connected to the left output of the load.
Zero is taken from the common zero bus (N). If damage occurs in the area controlled by the RCD, it will be removed from the circuit, and the second load will not be de-energized.
RCD in three-phase network
In the network of this type include a special three-phase RCD with eight contacts, or three single-phase.
The connection principle is completely identical. Mount it according to the scheme. Phases A, B and C supply power to loads rated for 380 V. If we consider each phase separately, it provides a series of 220 V single-phase consumers in tandem with cable N (0)
Manufacturers produce three-phase trip protection devices adapted to high leakage currents. They protect the wiring only from fire.
In order to protect people from the effects of electric current, single-phase two-pole RCDs are installed on the outgoing branches, tuned to a leakage current in the range of 10-30 mA. To cover up each insert automatic. In the circuit after the RCD, it is not possible to connect the working zero and ground.
RCD and three-phase circuit breakers
Let us examine in detail not quite the standard scheme assembled on a three-phase distribution board. It contains:
- three-phase input circuit breakers - 3 pcs .;
- three-phase residual current device - 1 pc .;
- single-phase RCD - 2 pcs .;
- single-pole single-phase automatic machines - 4 pcs.
From the first input automaton, the voltage goes to the second three-phase automaton through the upper terminals. From here, one phase goes to the first single-phase RCD, and the second to the next.
Single-phase RCDs mounted on the panel are bipolar, and automatic - single-pole. For the correct functioning of the protective device, it is necessary that the working zeros after it should not be connected anywhere else. Therefore, after each RCD, a zero bus is installed here.
When automata are not single, but double pole, a separate zero bus will not have to be installed. If two zero tires are combined, a false positive will occur.
Each of the single-pole RCD is designed for two machines (1-3, 2-4). The load is connected to the lower terminals of the machines.
Common grounding bus installed separately. Three phases enter the induction automat: L1, L2, L3, the working neutral conductor N and PE are protective.
Zero is connected to a common zero, and from it goes to all UZO. Then it goes to the load: from the first apparatus - to the three-phase one, and from the next single-phase ones - each to its own bus.
Although in this switchboard the input is three-phase, the separation of the wire into PEN and PE is not performed, since input five-wire. Three phases come to the shield, zero and ground.
Conclusions and useful video on the topic
The nuances of installing all the elements on the apartment panel:
Details of installation of the RCD:
UZO and automatic machines - the equipment technically difficult. It is advisable to install it in places where electric current can pose a threat to both the safety of people and home appliances.Mounting it involves taking many parameters into account, therefore, both the calculation and the installation are best performed by qualified specialists.