Before talking about the choice of a differential automaton, it should be explained how this issue has earned such popularity. Why are differential automata good? Of course, by the fact that the difavtomat is a device that provides the line not only protection against overload currents and overcurrents of short circuit, but also protection against leakage currents, that is, protection against electric shock from a person.

In other words, a single device provides the full range of necessary protections. This is very convenient because it saves space in the distribution board and simplifies installation. In some cases, money savings are also achieved, but this is relative, since a high-quality differential machine can be more expensive than a single ordinary machine and a residual current device (RCD). So, what is good for difavtomat, clearly. It remains to decide how to choose it ...

A circuit breaker, or, more simply, an automaton, is an electrical device familiar to almost everyone. Everyone knows that the machine disconnects the network when there are any problems in it. If not smart, then these problems are too much electric current. Excessive electric current is dangerous for all conductors and household electrical equipment to fail, possibly overheating, igniting, and, accordingly, a fire. Therefore, protection against high currents is a classic of electrical circuits, and it existed even at the dawn of electrification.

Any overcurrent protection device has two important tasks: to recognize an unnecessarily high current on time and correctly, to break the circuit before this current can cause any damage. At the same time, high currents can be divided into two categories: large currents caused by network congestion, for example ...

Quite often, this situation occurs: the circuit breaker is periodically knocked out and another larger rating is installed in its place, “so as not to knock out”. Why does the circuit breaker trip in this case, and what are the consequences of such a replacement?

The rating of the circuit breaker is selected in such a way as to protect the load line wire from overheating and melting of the insulation. The circuit breaker must disconnect the line from the load before the current reaches a critical value for the cable.

When devices of higher power (and therefore higher current) are turned on in lines that are not designed for this power, the cable overheats in the circuit, which leads to the thermal protection of the circuit breaker tripping, i.e. he "knocks out" ...

What can happen with a circuit breaker? Circuit breakers, like any other technical device, often fail. Among the possible reasons for this may be the systematic actuation of thermal protection and work at the limit of possibilities in general. In addition, there are cases when the device is not able to keep its setting after the first operation of the thermal release (not to be confused with the electromagnetic, that is, instantaneous release!). With such a malfunction, by the way, the machine outwardly will not be any different from its serviceable counterparts.

Very often, contact clamps and cases of modular circuit breakers burn out with insufficiently reliable electrical contact. Several non-twisted conductors of different sections can not be clamped well enough. There may be a screw defect in the clamping screw that does not allow the connection to be tightened properly ...

Modular circuit breakers can be found in every switchboard: at least in the apartment and entrance, at least in the workshop or office. Compact, easy to install, relatively inexpensive, reliable ... but how to make sure that they are really reliable?

Even the most eminent manufacturers of modular circuit breakers do not exclude a certain percentage of defects among their products that fall on store shelves. The situation is aggravated by the fact that machines are a pretty hot commodity, which is why they are willingly forged by various artisan workshops. The owners and workers of such workshops, usually located in China, have peculiar views on electrical safety and the principles of maximum current protection. The most unobvious malfunctions of defective and counterfeit modular equipment are associated with the incorrect operation of the releases ...

In accordance with current technical standards, the wiring in the apartment must be three-wire, and the outlet networks must be equipped with differential protection. There is no need to once again tell that all this is achievable is far from always. Therefore, RCDs and differential circuit breakers in apartment switchboards can still be seen infrequently - mainly for connecting a washing machine, which is usually located in the bathroom.

The fact is that according to the rules of the PUE, protection against leakage currents for power consumers in the bathroom is mandatory. And, installing a washing machine in the bathroom, experts often put in a shield a separate differential protection device for connecting it. However, it is not uncommon for a situation where the RCD or the difavtomat, to which the washing machine is connected, starts to constantly work and, what is called "spoil the nerves" ...

In the process of wiring, very often you hear the following question: what to choose - a residual current device (RCD) or a differential circuit breaker? So let's find out what is actually better. Differential automatic machine or RCD.

I will tell you definitely. The correct answer to this question does not exist, because The choice between an RCD and a differential automaton depends on numerous factors.

But still, I’ll try to explain and give you the opportunity to make a choice on my own with examples.

Point 1. Free space in the shield. First of all, you need to determine if there is free space on the DIN rail in your apartment panel ...

Electrical engineering is an exact science and here, unlike such ephemeral areas of human activity as, for example, design, there are clearly documented norms and rules (PUE, GOSTs, instructions), and not just “like” or “don't like”. Yes, the PUE is “the bible of an electrician” and the formidable phrase “read in the PUE” speaks of the importance, pumpability and great seriousness of those who said it.

But it turns out in life is always much more complicated everything is arranged than it is written even in the wisest books and these books can be interpreted in different ways. Particularly heated discussions among electricians in electrical forums raise questions related to the grounding of electrical installations and the installation of residual current devices (RCDs). It so happened that in our time in everyday life there are simultaneously two grounding systems TN-C and TN-C-S ...