Electrical wiring has long become the same mandatory engineering system for a home as water supply, heating and sewerage. True, it has one feature that must be taken into account when designing and creating. It is potentially dangerous for users and requires the use of various protective elements. One such component is a circuit breaker that trips when the current exceeds a certain threshold.
An automatic machine as an electrical device is designed for operation in 3-phase or single-phase networks, has a standardized form factor, Figure 1 and in most cases it is installed in a shield on DIN rail.
An additional benefit of installing the machine is a sharp decrease in the risk of fires, because any overload of the electrical the network is accompanied by the release of large amounts of heat, which leads to the ignition of insulation and other combustible objects in the nearest environment.
Approaches to the selection of the rated operating current of the machine
The industry serially produces several types of circuit breakers for operating current or amperage. The selection of a specific model for this parameter is in the area of responsibility of the author of the project and is most often carried out at the time of drawing up a structural diagram of the network, Figure 2.
In this part, specialists, similarly to blunt-tips and pointed-tips from “Gulliver's Adventures”, are divided into two irreconcilable camps.
The first of them choose the nominal value of the machine according to the load capacity of the sockets (in common parlance - “sockets”), the second - by a similar indicator of wires or, which is equivalent in cross-section of the conductor in accordance with the table (they refer to the camp "Cablemen").
“Sockets” take the principle of the weak link as a basis, “cable operators” protect the linear part of the wiring with an automatic machine as its key component.
What approach to choose when developing a project?
The author of these lines, while recognizing the certain correctness of the “outlet” in terms of choosing the amperage of the machines, nevertheless, belongs to the supporters of the “cable” approach.
The main arguments for this choice are as follows:
- The “socket” approach forcefully leads to the need to use 10-ampere circuit breakers and to increase the number of separate beams, ie. overload wiring turns out to be "overprotected" and, accordingly, more expensive even if 1.5 mm cores are used cable;
- the probability of overloading the outlet in real conditions is extremely small, since the manufacturers of household appliances initially take as a basis the maximum power consumption of their products the capabilities of typical household sockets.
To be fair, let us point out the weak point of the second position. Its essence lies in the fact that the outlet can be overloaded even with typical appliances, if you plug them in through a multi-outlet extension cord, Figure 3 or, even worse, through a traditional tee, Figure 4. The likelihood of such an event is reduced by installing the required number of outlets in the room. In addition, the common sense of the users is of some importance, although there is little hope for it.
Conclusion
As you can see, there is no unambiguous decision in favor of choosing one or another value of amperage, and each specialist must solve this issue for himself individually. There is only one thing in common in this matter: you must initially install a high-quality machine, and during operation, monitor its serviceability.