The appliance may be damaged in the electrical wiring. In order to reduce the risk of hazards that can lead to electric shock, protective devices are installed. These are household appliances that can perform a variety of functions. In the article we will consider the differences between the machine and the RCD. It should be noted that the differential machine, residual current device and circuit breaker installed in the complex will significantly increase the level of electrical safety. They will make it much faster to turn off all the electrical wiring at home. As a result, a person will not receive electrical injury if he touches the bare wiring. But let's talk about what are the differences between the machine and the RCD.
Power failures
Let's first consider what kind of malfunctions can occur inelectrical wiring. There are many breakdowns that manifest themselves as follows:
- A short circuit that occurs when the load resistance line reaches an extremely small value. This usually happens when shunting voltage circuits with metal objects.
- Leakage currents appear. They occur when the insulation is broken, as well as through accidentally closed circuits to the ground.
- Overloading wires that are installed in houses and apartments. As a result, a very large current is consumed. If the wiring is outdated, then the current-carrying cores begin to get very hot. In this case, the insulating material is constantly exposed to high temperature, and as a result, its dielectric properties are lost.
How things could get worse
But do not think that this is the worst thing that awaits you. The situation may worsen when malfunctions occur if the following points occur:
- The house has old aluminum wiring, which is several decades old. If it has been used for a long time, it will gradually become unusable. And you need to take into account that the power of consumers is quite high. And modern electrical appliances wiring is unlikely to be able to withstand normally.
- The use of ruined protection devices and their poor-quality installation. Even if new electrical wiring is used, it may cause a malfunction as well as a fire.
In order to greatly simplify the explanation of what the differences between protection devices are, we willtalk only about those devices that are used in a single-phase network. It is worth noting that structures designed for use in a three-phase network have similar principles of operation and operate according to the same laws. It is necessary to carefully consider the features of the operation of the devices in order to understand what are the differences between the machine and the RCD.
Circuit breakers
Today, the industry produces a large number of types of circuit breakers. They can save you both from the effects of a short circuit and from significant heating of the wires. But it is necessary to consider the differences between the RCD and the differential automaton, as well as the design features of these devices. To provide protection, the following elements are used in the design:
- Magnetic quick release coil for breaking the circuit. It allows you to eliminate the currents that occur during a short circuit. An arcing system is also installed here, which allows you to get rid of the spark that occurs when the contacts open.
- Thermal release that works with a certain time delay. It is made of a bimetallic plate, which allows you to eliminate overloads that occur inside the electrical circuit.
Protective circuit breakers for residential premises are included only in the “phase” wire, they allow you to control only those currents that pass through it. It is worth paying attention to the fact that it does not react in any way to leaks that may occur during operation of the equipment.
Device forsafety shutdown
The protection device is installed in the break of two wires - "zero" and "phase". With the help of this device, it is possible to constantly compare the currents that circulate in the wires. Also, the device can independently calculate the difference in currents. In the case when the current that comes out of "zero" is the same in magnitude as the one that passes through the "phase" wire, the circuit does not turn off. Residual current device allows it to function.
As soon as there are small deviations in these values that do not affect the safety of people, the device also does not block the power supply.
With the help of a residual current device, voltage is removed from the wires that fit it, if leakage currents with a very high value appear inside the circuit. This is especially true for those currents that can harm human he alth or electrical equipment operating in the house. To set up residual current devices, you need to select a specific installation current. When choosing the optimal value, you will eliminate false trips, as well as create an opportunity for reliable operation of the protection and getting rid of leakage currents.
But the whole design of this device does not have any protection against short circuits, even overloads can disrupt the operation of the RCD. Therefore, it is necessary to protect the device itself from short circuits and overheating of the wiring. In electrical circuits, a simple automatic circuit is usually connected in series with the RCD.switch.
Differential circuit breakers
The device of such a device is even more complex than an RCD or a circuit breaker. With its help, it turns out to eliminate all types of faults, including overload, short circuit, leakage. These are the malfunctions that can occur in the electrical wiring of an apartment or house. The design of the differential machine has thermal and electromagnetic releases. They protect the built-in residual current circuit breaker.
The differential circuit breaker is made in a single module, it has the functions of both a residual current device and a circuit breaker. In other words, you can replace two at once with one device. Taking into account what was said above, the conclusion suggests itself that it is necessary to further compare the characteristics of only two elements:
- A block consisting of a residual current device and a circuit breaker.
- Differential circuit breaker.
This is the most technically correct and justified comparison. Next, we will consider the main differences between the RCD and the differential automaton, we will analyze all the nuances.
Dimensions
It is worth noting that the devices are modular, they can be mounted on a din-rail, which will significantly reduce the space required for installation in an apartment or in any electrical panel. But it should also be noted that even such an approach cannot always eliminate the lack of space forcompleting electrical wiring with other protection devices.
RCD and circuit breaker, as a rule, are made in separate cases. Installation is also carried out separately. But they can be installed on the same rail. As for the differential circuit breaker, it is enclosed in one housing. In other words, it contains two complex devices at once. Together they provide reliable protection. Differences diff. the machine and the RCD are significant, we will talk about them later in the article.
This point must be taken into account when creating an electrical work project in a new house or apartment. Based on this, it is necessary to choose shields, provide a small margin of space, if you suddenly have to finalize the circuit. But during the reconstruction of electrical wiring or during minor repairs, electrical panels are not always replaced. Therefore, the problem of lack of space in them remains.
What tasks do devices perform
If you take a quick look, then the circuit breaker paired with a residual current device and a differential circuit breaker allow you to solve similar issues. Dif. the machine and RCD have significant differences, but let's be specific. For example, you can install a block of several sockets in the kitchen, which will power various appliances, the power of which differs significantly. It can be a dishwasher, refrigerator, microwave oven, electric kettle and so on. All these devices connect to the network randomly, they createloads with a random variable.
In some cases, the power of simultaneously operating devices may exceed the rated value of the protection, which creates an overcurrent. Moreover, if you have a differential machine installed, you will have to replace it with a powerful one. If you use an RCD, it will be sufficient to install a new circuit breaker, designed for a higher tripping current. But which is better - RCD or automatic?
In the event that you need to protect a specific electrical device that is connected to a separate line, then it is more reasonable to use a differential machine. But it must be selected strictly according to the technical characteristics of the consumer.
How to install
Let's talk about mounting devices. As you understand, the only difference in DIN rail fasteners is whether one or two modules need to be installed. But once you get to the wiring, the amount of work changes. If the residual current device and dif. the machine is installed in the gap of the "zero" and "phase" wires, then jumpers are also needed for the machine. They will allow you to connect it to the "phase" wire in series with the residual current device. In some cases, this complicates the assembly of the entire circuit. The differential RCD also contains a conventional circuit breaker, so the cost of such a device is high.
Reliability and quality
Among experienced electricians, there is an opinion that the performance and durability of protection devices may depend not onlyhow they were assembled at the factory. It is very important how complex the design of this element is, how many parts are present in its design. And also how difficult it is to bring and adjust the device. From this point of view, the differential automaton is the most difficult, since more operations must be performed to configure it.
But this point of view is rather controversial, it is not very correct to apply it literally to all devices that are produced by the industry. In some cases, a differential machine works much more efficiently and reliably than a duo of a residual current device and a circuit breaker. RCD and difavtomat are different, but they allow you to perform almost identical tasks.
Replacement & Repairability
It is worth noting that breakdowns can occur on almost any protection device. If it is not possible to eliminate it immediately, then the protection device may fail. Therefore, you will have to buy a new device. The cost of a differential machine is much higher than a residual current device and a simple circuit breaker. And in the event that you install an RCD and a circuit breaker, then in the event of a breakdown one of the devices will be intact, it will not be necessary to replace it. And this will significantly reduce the cost of repairs.
In the event that any protection device (for example, an automatic differential switch) breaks down, thenall consumers that are powered through it must be turned off. If the RCD is faulty, then it is allowed to shunt its circuits and supply power only through the circuit breaker. As you understand, if there was a malfunction in the differential machine, then you will not be able to “cheat” like that. You will need to replace it with a new one or install a regular circuit breaker for a certain time.
How they work in different situations
And now about the difference between an RCD and an automatic machine in terms of circuitry. The circuit for monitoring the leakage currents of a differential machine and a residual current device can be executed on various element bases:
- Electromechanical relay design that does not require additional power supplies for normal system operation.
- With the help of microprocessor or electronic technologies, which without fail need a power supply capable of delivering a stable voltage.
If the wires suitable for the devices are in good condition, then they work almost the same. But if malfunctions appear in the circuit, for example, the contact of one wire (“zero”) breaks, then you can immediately see the positive qualities of models built according to the relay circuit. It should also be noted that they are more reliable and work better in outdated two-wire circuits.
How to determine the cause of a protection trip
As soon as the RCD is triggered, you can immediately understand that leakage currents have appeared in the wiring diagram, so you have tocheck the condition and quality of the insulation of the area that is protected by the device. When the circuit breaker trips, it can be understood that the reason is that an overload has occurred in the circuit or a short circuit. But if the differential machine is turned off, then it takes much longer to search for the cause of this phenomenon. As you can see, the difference between the RCD and the differential machine is big - it is difficult to find the cause of the breakdown in the latter.
And you will have to carefully understand both the insulation resistance and the loads that are created in the network. It is almost impossible to immediately identify the cause of the operation, you can only guess. But today you can find expensive designs of differential automata on sale, on which indicators are installed that signal why the protection worked.
Marking on the case
And now consider the differential. automatic and RCD. What is the difference between these devices. The cases of the differential machine and the residual current device are identical, therefore, they have the same appearance, there is a lever for manual activation, a button labeled "Test", the terminal blocks for connecting wires are also the same. But you can distinguish them by the inscriptions and diagrams that are present on the front side. Be sure to indicate on the plates of the electrical appliance which load values \u200b\u200bare nominal.
It is also mandatory to indicate which leakage current can be monitored, the voltage in the wiring, as well as the connection diagraminternal components of the instrument. It is mandatory to show the differential current circuit transformer being controlled.
There is no current protection in the residual current device, so it is not shown on the diagram. As for the differential machine, it is present in its design, therefore it should be shown on the case. What is the difference between an RCD and an automatic machine - you now know, it remains only to choose the right thing for you.
As for the devices produced by the domestic industry, they are marked in such a way that the buyer can independently navigate them. Directly on the case, in the most prominent place, it is indicated that the device is a differential. automatic. In the case of a residual current device, this marking is located on the back wall.
"VD" means that it is a differential switch. It is worth noting that from a technical point of view, this is the correct designation option. This device only responds to leakage current, but does not protect against overcurrent or short circuit. As a rule, protective shutdown devices are marked with such letters. There is also an abbreviation "AVDT". She says that the design has a circuit breaker. Strictly speaking, this is a differential automaton. Therefore, if you decide what to choose - RCD or automatic, put a better differential. Although it is more expensive, it is more modern and efficient.
