If you do the wiring in the apartment yourself, then sooner or later the time comes when the home master is faced with the need to assemble the introductory switchboard. And here the question arises, which automation is better to install in order to protect the home power network as much as possible. Many do not understand how some devices differ from others. Today it is worth shedding light on such complexities of choice. The article will discuss how to distinguish an RCD from a difavtomat, what functions these modular elements perform and what is better to choose to protect your loved ones from possible electric shock, and the power network from overloads and short circuits.
Appointment of protective automation: is there a need for installation
Such equipment, depending on the type, can provide security in various ways. For example, the difference between an RCD and a differential automaton lies primarily in functionality. Butin order to make it easier for a respected reader to understand what exactly are the differences between some elements from others, it is worth considering in detail their characteristics. Only after their full analysis will it be possible to answer this question.
Residual current device: how it works
RCD is responsible for cutting off the power supply in the event of a current leakage in the electrical network, ensuring human safety. Such automation is able to protect the owner in the event of a breakdown of the phase wire on the metal case of the household appliance. It also solves safety issues in the rather common situation when the washing machine is installed in the bathroom - in this case, dampness causes mild discharges that the user feels when in contact with the surface of the unit.
A residual current device differs in functionality from a circuit breaker in that it reacts only to current leakage and does not turn off in case of short circuits or overloads. For this reason, RCDs require additional protection, which is AB.
The differences between residual current devices and automatic machines are clear. It remains to understand how RCDs differ from differential automata. The difference can be understood by considering the characteristics of RCBOs.
Difaautomats and their functions
Such devices are universal. They combine the functions of residual current devices and circuit breakers. Of course, they cost a littlehigher, but sometimes there is simply no other way out than installing a RCBO. The fact is that the RCD / AV bundle occupies 3 modular places on the DIN rail in the switch cabinet, while the difavtomat, which does not require additional protection, is only 2. Today, more miniature devices of this type have appeared. Their dimensions are equal to the dimensions of a single-pole machine, however, judging by user reviews, their service life is much less than that of full-fledged RCBOs.
It turns out that installing a difavtomat instead of an RCD is quite simple - these actions do not require the purchase of additional equipment. But if an RCBO was originally installed, then when purchasing a residual current device, you will have to spend money on an AB, which will protect it from network overloads and short circuits.
RCD or differential machine: visual differences
It is difficult for an uninitiated person to understand what device is in front of him. Externally, the RCD is practically no different from the RCBO. However, it will be quite easy for a knowledgeable home master to figure it out. So how to distinguish an RCD from a difavtomat visually? The main thing here is to understand what the markings on the front panel mean.
With Russian-made products, everything is quite simple. They clearly indicate which device a person holds in his hands. On the front panel, "difavtomat" or "AVDT" can be printed. If there are no such markings, you need to pay attention to the alphanumeric designation.
The number followed by the letter "A" indicates thatin front of the home master, a residual current device. For example, if the marking is 16A, then this is an RCD with a rated current load of 16 amperes. If the letter designation comes before the numerical one (it can be the letters "B", "C" or "D"), then this is an RCBO. For household networks, devices with the type of time-current characteristic "C" are used.
Marking RCD and difavtomat can say a lot to a knowledgeable person. It indicates not only the type and rated current load. On the front panel, you can find the breaking capacity according to GOST, find out about the presence or absence of a thermal and electromagnetic release. The marking will also indicate the current limiting class.
Popular protective device manufacturers among consumers
The number of firms offering similar products on the shelves of Russian stores is growing steadily. However, it is difficult for young brands to find their niche in the electrical appliance market. Among consumers, brands that have been producing protective equipment for several years and have already managed to prove themselves on the good side, thanks to the quality and reliability of products, are popular. One of these brands can be called ABB. This company has long been known to the Russian buyer, people treat its products with confidence. Thanks to this, RCDs and ABB difavtomatov do not lie on the shelves.
Only the pricing policy of the Italians, who produce products under this brand, is surprising. The cost of devices with almost identical characteristics can vary significantly. For comparison, let's take 2 ABB difavtomat withwith a rated current load of 16 A and a leakage trip of 30 mA. The price of devices is (by models):
- DS901 – RUB 1600
- DS201 – RUB 5100
But in the end, it is up to the home master to decide what to buy.
Connection of protective automation in the switch cabinet
The solution to this issue requires care and accuracy. It is not enough to know how to distinguish an RCD from a difavtomat. It is required to be able to connect both of these devices correctly. A respected reader has probably already understood that switching the RCD requires additional installation of an AB, so the circuit here is a little more complicated, but not so much that it was impossible to figure it out. It is necessary to make a reservation right away that in order to provide reliable protection, both devices require high-quality and properly functioning grounding. It is worth carefully considering the question of how to connect a difavtomat and RCD.
Residual current device: how to install
The work algorithm is as follows. After the electricity meter, a circuit breaker is installed, and only after it is the RCD. When switching, it is necessary to pay attention to the protective earth - neither in the switch cabinet nor in the apartment sockets, it should come into contact with the neutral wire. Otherwise, the RCD will periodically work for no reason, leaving the apartment without electricity.
Commutation of the residual current circuit breaker
Similar equipment is connected in the same way - from aboveinput of phase and neutral conductors, from below the voltage output to the apartment. The difference lies in the absence of the need to install the machine in front of the RCBO. It should be noted that if the phase and neutral conductors are incorrectly connected, unreasonable disconnections can also be observed, so you should carefully consider the markings of the contacts on the front panel. Information on the switching order of a particular device can be found in the diagram, which is located on the side.
Which is better - difavtomat or RCD?
This is a question that still has a lot of controversy. It is the second most popular among Internet users, after the main one - how to distinguish an RCD from a difavtomat. Specialists and home craftsmen were divided into 2 camps. The first argue that the installation of RCBOs is simpler, the device takes up less space in the shield, which automatically makes it more in demand. The latter, on the contrary, say that his problem lies in universality. Indeed, when installing the RCD / AV bundle, it is possible to replace only one node, in case of failure, while in the event of a RCBO failure, more expensive equipment will have to be purchased as a whole. In addition, there is a problem with determining the cause of the operation. It is not clear why the power supply was turned off - due to overload or leakage. If the bundle is installed, this question does not arise.
You can argue on this topic for a long time, but there are times when there is no other way out than installing a RCBO for a reasonlack of free modular space on the DIN rail. In such cases, the question “what is better” fades into the background, giving way to practicality.
RCD and difavtomat: designation on the diagram
It's rather strange, but GOST does not give any explanations about how the residual current device should look like on the diagram. Most often, each electrician marks such a device in his own way. Over the years, a certain generally accepted image has developed (it can be seen below), which is used with certain deviations. Even if you pay attention to the devices themselves, the schematic images on the cases of devices of different brands are different.
GOST also does not provide specific rules for the designation of a residual current circuit breaker. Such an omission causes a lot of problems in reading circuits as a result of misunderstanding - after all, every electrician believes that the image he made is the only correct one. Below you can see the generally accepted image. It is not a fact that in the scheme that fell into the hands it will be absolutely identical, but it will be possible to catch the general. This will make it a little easier to understand what exactly is installed in a particular distribution cabinet.
After reading the generally accepted schematic images, it becomes clear how to distinguish an RCD from a difavtomat when reading projects.
Let's sum up today's conversation
When choosing protective devices for your home power network,you should be very careful. Before going to the store, you need to decide what equipment will be installed in the switch cabinet. Being near the counter, you need to carefully study the markings on the device case so as not to buy a differential current circuit breaker instead of an RCD and vice versa. It makes sense to familiarize yourself with the certificates and approvals for protective equipment, which must be kept by the seller without fail. But in the end, no matter what the home master chooses, RCD or RCBO, the main thing is that the device performs the required functions to protect not only the network, but also the life of the owner.
