Protective automation of the home power network, located in the switch cabinet, is a necessity dictated by security. A lot depends on how well it is chosen. Such equipment can cut off the power supply in case of overload, power surges or current leakage that can harm a person. In addition, each device is responsible for its own protection area. Today we will talk about how the RCD differs from the machine, what functions these devices perform and how they are arranged.
Home electrical protection devices: definitions and general information
First of all, you should understand how such automation differs and in what cases its use is justified. Such devices are divided into 4 main types:
- Automatic switches (AB).
- RCD.
- Residual current circuit breakers (RCBOs).
- Voltage control relay (PH).
To make it easier to understand,how the RCD differs from the differential machine (for example), it is worth analyzing in more detail what each of the listed devices is responsible for.
What is AV and what functions does it perform
A protective circuit breaker is a complex device consisting of a static solenoid and a movable rod located in it. With stable operation of the electrical network, a current flows through the solenoid, which does not affect the functionality of the machine. If many different devices with high power consumption are connected to the line, the parameters change. Increasing the current in the solenoid pushes out the movable stem, which acts on the contact group, opening the circuit, as a result of which the voltage supply to the home electrical group is stopped.
Of all the protective automation devices, AB is considered the simplest. Its functionality allows not to protect the home network from overloads and short circuits, but to prevent the consequences of such cases, such as overheating and ignition of the wiring and the possible subsequent occurrence of a fire. And what is the difference between an ordinary machine and an RCD?
Residual current device: equipment features
The difference between the RCD is that it performs a completely different function, the purpose of which is to ensure the safety of not electrical wiring, but of a person. The device is activated when a situation arises when the current-carrying wire comes into contact with the metal case of the household appliance. In this case, a leak occursfixes RCD. This causes a cutoff and a power outage. But the main thing that distinguishes the RCD from the circuit breaker is the lack of response to overloads and short circuits. If there is no AB in the circuit, and a short circuit occurs in the home electrical network, the device will simply burn out, and there will be no power outage.
Such features of protective equipment dictate certain rules for their use. In distribution cabinets, a pair connection of RCDs and automatic machines is used, which ensures maximum safety for both humans and electrical wiring of household appliances.
RCBO: what is it and what does it serve
Distribution cabinets are often quite small and it is not possible to accommodate all the protection devices that are planned in them. You can install a larger box, but sometimes for this it is necessary to expand the niche (with its built-in location), which is not always possible. The way out of this situation will be the use of a differential automaton, which performs the functions of two devices at once - AV and RCD, but takes up less space. In addition, installation in this case is simplified.
It's worth figuring out the difference between diff. RCD machines. The answer to this question will be a short video in which everything is described in detail.
Such combined devices have many advantages, but there are also some negative sides. It is worth dwelling on the pros and cons of residual current circuit breakers in more detail.
Advantages and disadvantages of a combined device before a bunch of AB + RCD
Information about the pros and cons of AVTD for ease of perception and clarity is presented in the form of a comparative table.
| Positive aspects of the differential automaton | Negative qualities of RCBOs |
| Takes up less space on a DIN rail. 2 modular locations are required for mounting, as opposed to a bundle of 2 units which requires 3. | It is difficult to determine the cause of the trip - leakage or overload. When applying the link, the answer will be obvious. |
| Wiring RCBOs is much easier, reducing the risk of incorrect installation. | The cost of the device is higher than that of a conventional machine and RCD combined. |
| Does not require additional protection - the built-in circuit breaker is enough. |
The failure of one part means a complete replacement of the equipment, while the use of two devices will have to buy only an AB or residual current device. |
The question "what is the difference between a differentiated automaton and an RCD" has yet to be returned, but now it makes sense to understand what the RN is.
Voltage control relay: application features
Power surges and drops are not uncommon for our electrical grids. Houses located in private sectors are especially susceptible to them. Such changes can easilydisable complex, expensive household appliances and electronics. But the purchase of stabilizers or uninterruptible power supplies is not cheap, and it is not always justified. The best option would be to install a voltage monitoring relay, the upper and lower thresholds of which are set by the user.
When the voltage drops below or rises above the programmed values, the device turns off the power supply for a certain time. After it has passed, the device closes the circuit again. If the reason for the operation is eliminated, the voltage is supplied in the normal mode until the next similar situation occurs. This allows you to protect household appliances and electronics from the harmful effects of voltage surges. Also, the voltage control relay will save in the event of a short circuit of one of the phases to the neutral wire. This often happens when, in the private sector, the strands of the overhead power line sag from time to time. In strong winds, the phase wire overlaps with zero. As a result of this, 380V can be supplied to the devices. In such a situation, a voltage relay will prevent dangerous current from reaching devices connected to the home power network.
What is the difference between an RCD and a differential machine and what is the similarity of devices
If we take into account the size, then everything is the same here. The residual current device occupies 2 modular positions, as does the residual current circuit breaker. However, as already mentioned, if a short occurs on a line that is equipped only with an RCD,short circuit, no cutoff will occur, the wires will start to heat up, which will cause them to ignite and fire. The differential automaton will not allow such an outcome. In case of overload or short circuit, it will instantly turn off the power supply, like a conventional AB. But what distinguishes the RCD from the machine is the ability to detect current leakage.
Most people are familiar with the discomfort when touching the body of a household appliance, a slight electric shock is felt. This may be due to high humidity. If an insulation breakdown occurs, then the discharge can be many times stronger, and the consequences are very deplorable. The RCD is designed specifically to fix such leaks and turn off the power when they occur. The fact is that in such a situation there is a difference in the current entering through the phase conductor and returning through the zero one. It is taken into account by the residual current device.
It remains to answer one more question: what is the difference between a difavtomat and an RCD? The residual current circuit breaker, unlike the residual current device, reacts not only to leakage, but also to various overloads. If several devices with high power consumption are connected to the sockets of one line, the RCBO will interrupt the power supply, thereby protecting the wiring from heating, and the contacts of the connection points from burning out.
Rules for installing equipment in a switchboard
Despite the fact that the residual current device can be switched without grounding, complete safety in this case fromdevices do not have to wait. However, in some cases there is no other way. It is not difficult to figure out how to properly connect the RCD and the machine, but the work requires maximum care and accuracy. The first thing to pay attention to during installation is the presence or absence of a ground bus in the switchboard. It must be installed separately from the zero bar and should not come into contact with it in any way.
Only a phase wire is connected to a conventional machine. When placing it on a DIN rail, you should make sure that the inscriptions on the front are not upside down. With the correct location, the upper contact will be introductory, and from the lower voltage it will go to the home network or other automation.
Connecting an RCD is somewhat different. Here, 2 wires come to the upper contacts - phase and zero, and the lower terminals are tap-off. First you need to check the operability of the residual current device. To do this, the flag switches to the “on” position and the “test” button is pressed - the RCD should work in the same way as in case of a leak.
Useful information! If, after installation, the residual current device intermittently trips without a specific reason, the connection or wiring of the sockets may be incorrect. You will have to check all connection points and junction boxes. Perhaps, in one of the places, the connection of the neutral and ground wires is allowed.
Criteria for selecting RCDs and circuit breakers
Before purchasing such protective equipment, you need to determinetechnical parameters that are necessary for a particular amount of household appliances and its power consumption. Here one should be guided not by information about how the RCD differs from the machine, but, on the contrary, by the similarity of some characteristics. It is assumed that these devices will work in pairs, which means that the maximum current load of the devices must be the same, although a lower indicator is allowed on AB.
Before you pick up an RCD and an automatic machine, you need to add the current load of all household appliances into groups. You will also need the total amount for all lines. If this figure does not exceed 16A, it is quite possible to get by with one RCD. Otherwise, you will have to purchase devices by the number of groups or protect individual lines that feed more expensive equipment.
As for the cost, well-known brands will cost more. But experts do not advise using the opportunity to purchase cheap protective equipment from unknown manufacturers. Such an acquisition, at best, will require replacement after a short period of time. At worst, it may not work at the right time, which will lead to sad consequences.
You should not purchase such equipment via the Internet - RCDs, RCBOs and ABs may be inoperative, and in this case a return or exchange becomes quite problematic. The best option would be to buy protective automation in large, well-established electrical engineering stores, which are staffed by knowledgeablethe specifics of the goods sellers-consultants. They can talk about the product, and if the outlet values its reputation, then they will not conceal the negative aspects of the products from the buyer.
Checking the performance of the RCD when buying
When purchasing a residual current device in a regular store, you need to understand whether it performs its functions. To do this is quite simple. Before going to the store, you need to prepare an ordinary 1.5V battery, 2 pieces of wire, each about 10 cm long with stripped ends, and a screwdriver. The verification algorithm is as follows:
- Wires are connected to the two contacts of the selected RCD (the input and output terminals are used, phase or zero - it does not matter).
- The second bare ends, when the device is turned on, are connected to the plus and minus of the battery. If the RCD is operational, it will trip.
The trigger is pretty simple. By connecting the battery, the user creates a certain voltage on one of the coils, while the second remains without load. The RCD considers this state of affairs as a leak and trips. This method is simple and safe, and therefore feasible at any outlet. It is possible to check the device installed in the switchboard in a similar way, but for this it is necessary to disconnect the wires suitable for it.
What to choose?
The answer to this question everyone should give on their own based on the size of the switchboard and financial capabilities. Understanding what is differentRCD from the machine and AVDT, it will not be difficult to make a decision. You need to understand that you should not save on your safety. And how the protection will be carried out is not so important. The main thing is that it should be comprehensive and perform its duties with high quality.
