When assembling a new electrical shield or replacing old equipment, the owner of the house inevitably raises the question of the sequence of installation of protective devices. Electric current is invisible, but its consequences when errors are made can be fatal, so each element of the circuit must stand in its place. Many people mistakenly believe that the choice of the location switch-off It is only a matter of convenience of installation.
In fact, it depends not only on the security of wiring, but also the legal purity of your actions in the face of the energy supplying organization. There are strict regulations governing the procedure for connection, and their violation can lead to fines or refusal to seal the meter.
In this article, we will discuss in detail where it should be. enter-machineWhat are the exceptions and why are the energy sales so tightly controlled by this node? You will understand the difference between security requirements and commercial electricity metering rules.
Regulatory framework and requirements of IUE
The main document regulating the device of electrical installations are the Rules of the device of electrical installations, or abbreviated PUE. It is in this set of rules that all technical requirements are prescribed to ensure the safety of the operation of electric grids. According to the current regulations, before the metering device of electricity should be able to completely disconnect the voltage.
This requirement is dictated by the need to safely replace or maintain the meter. If the automatic switch is installed after the meter, then when it is replaced, the electrician is forced to work under voltage, which is strictly prohibited by safety rules. Introductory machine It allows you to break the chain to the meter, de-energizing the entire system.
However, there is a conflict of interest here. On the one hand, safety regulations require a break to the meter. On the other hand, energy supply organizations require that this gap be unavailable to the consumer to prevent the possibility of theft of electricity. Therefore switch-off, installed to the counter, must be placed in a special box or shield, which is subject to sealing.
⚠️ Attention: Installation of the machine to the meter without the possibility of its filling by representatives of energy sales is a direct violation of the power supply contract and can be regarded as an attempt to steal resources.
It is also worth considering the requirements of local network companies, which may have their own specifications. In some regions, it is required to install an introductory switch or automatic machine in a separate street shield, access to which only the controlling organization has. This creates additional difficulties for the owner, but is a prerequisite for connection.
Connection scheme: machine to the counter
Installation switch-off before the metering device is the most common and technically competent scheme. In this case, the cable from the external network first gets to the entrance of the machine, and from its output goes directly to the counter. This sequence allows you to protect not only the internal wiring of the house, but also the meter itself from short circuits that may occur inside the meter.
The main advantage of such a scheme is the possibility of a complete replacement of equipment without calling the employees of the power grid to turn off the line. You just click the switch or the machine, and the entire circuit to the meter is de-energized. This is especially important in emergency situations or emergency situations.
As mentioned, however, this machine must be protected from unauthorized access. For this purpose, special plastic boxes with ears for fillings or entire record and distribution boards are used. Inside such a box is usually installed automatic, and sometimes the meter itself, if the design allows.
Use machines with additional contacts to install filling plugs if your local power supply requires just such protection from interference.
It is important to choose the right denomination switch-off. It must match the allocated power to the home and the section of the inlet cable. Too powerful machine will not perform its protective function, and too weak will constantly knock out at peak loads.
Connection scheme: machine after the counter
The option of installing the machine after the counter is less common, but also has the right to exist in certain conditions. In this scheme, the cable from the external network goes immediately to the entrance of the meter, and already from the exit of the metering device is connected. enter-machine. This configuration is often found in older homes or where meters are installed indoors without the possibility of removing protection from the outside.
The main disadvantage of this scheme is the inability to safely replace the meter itself. Since the voltage is directly supplied to the terminals of the meter, it requires a power outage throughout the house or on the drive-in, which is not always possible. In addition, in the case of a short circuit inside the meter, the protection will work only if the machine is immediately behind it, but the meter itself may already suffer.
However, from the point of view of energy sales companies, such a scheme is more preferable, since it eliminates the possibility of connecting the load bypassing the meter to the break point. But even in this case, it is often required to install a separate switching machine to the meter, which is also sealed.
| Comparison parameter | Automatic to the counter | Post-counter machine |
|---|---|---|
| Safety of counter replacement | High (can be de-energized) | Low (network shutdown required) |
| Counter protection against KZ | There is. | No (or partial) |
| Requirements for filling | Mandatory automatic seal | The seal on the terminal lid |
| Prevalence | High (modern standard) | Medium (often in the old fund) |
☑️ Checking the connection scheme
The problem of electricity theft and sealing
Issue of installation enter-automatic It is closely related to the problem of control of electricity consumption. Power supply organizations face various ways of illegal power take-off, and having a non-sealed circuit break to the meter is one of the easiest ways to manipulate. That is why the control of this node is so strictly regulated.
Sealing is carried out with special lead or plastic seals, as well as stickers that are destroyed when you try to open. Violation of the integrity of the seal entails recalculation of consumption by the maximum cross-section of the cable for the entire period, which can cost the owner tens of times more than the real cost of electricity.
⚠️ Attention: Self-removal of the seal from the input machine or counter, even to replace the faulty device is prohibited and punishable by large fines.
Modern. switch-off often have a design that allows you to install the seal directly on the lever or terminals, blocking access to the screws. This provides reliable protection against unauthorized change of parameters or connection.
What happens if you tear the seal?
If you tear the seal yourself, at the next inspection, the controllers will draw up an act of unrecorded consumption. You will be given the amount of energy based on the section of the introductory cable and the number of hours in a day for the entire period since the last check (up to 3 years). The amount can reach hundreds of thousands of rubles.
Selection of denomination and type of machine
Choice switch-off It’s not just about buying the first box you find. Many factors must be considered: material and cable cross-section, type of load, temperature regime. An error in choice can lead to either permanent false blackouts or a fire.
For private houses and apartments, automatic machines with characteristics are most often used "C". They are designed to work with active-inductive loads, such as household appliances, lighting and heating appliances. The “B” characteristic is more sensitive and may not be suitable for introductory lines with large starting currents, and the “D” characteristic is for motors.
The nominal current of the machine should be less than or equal to the maximum allowable current for your input cable. For example, for a copper cable with a cross section of 10 mm2 laid openly, the permissible current can be about 50-60 A. Putting the machine on 63 A in this case is risky, it is better to choose 50 A.
- 🔌 Double-pole machine - Mandatory for single-phase input, breaks both phase and zero.
- 🏠 Tripole machine - used for three-phase input (380 V), breaks all three phases.
- ❄️ Temperature regime Keep in mind that in the outdoor shield in winter, the machine can work incorrectly without heating or special thermal compensation.
Never use conventional low-power socket machines or, conversely, powerful industrial switches without thermal protection instead of the input machine.
Frequent errors in installation of the introductory node
Even experienced electricians sometimes make mistakes that can cost the homeowner peace of mind and money. One of the most common mistakes is to use instead of switch-off a conventional switch or load switch. Such devices do not have thermal and electromagnetic protection and will not turn off the line when short circuit.
Another mistake is the wrong connection of the wires. In single-pole machines, the top and bottom are often confused, although modern modular devices allow power to be connected from either side. However, for two- and three-pole automata, it is important to follow the marking and not confuse phases with zero if the zero terminal does not have the designation "N".
Also often forget about the quality of the extension of contacts. Aluminum wires have the property of "swim" under load, so the connection requires periodic lifting. If an aluminum inlet cable is used, the transition to copper inside the shield must be made through special transition terminals or tips to avoid galvanic pairing and oxidation.
⚠️ Note: The use of twists to connect the input cable to the machine is strictly prohibited. Use only certified tips and terminal clamps.
Do not forget about the color marking of the wires. The phase should be of the same color (usually white, red or brown), zero blue, and grounding yellow-green. This will make it easier to continue maintenance and troubleshooting.
FAQ: Answers to Frequently Asked Questions
Can I replace the introductory machine myself?
Theoretically, you can replace the device, but if the machine stands to the counter and sealed, independent intervention is prohibited. You will need to call a representative of the energy sales to remove seals or have a contract with a service organization that is entitled to such work.
Which machine is better: single-pole or two-pole on the input?
For a private house and apartment, it is highly recommended to use a two-pole machine. It breaks both phase and zero at the same time, which ensures complete shutdown of the network during repair and protects against the emergence of potential on zero wire in the event of a line accident.
What if the energy supply requires to bring the machine outdoors?
This requirement is legal if it is prescribed in the technical conditions for connection. You will have to install a sealed street shield (metal or plastic with IP54 protection and above) and place the introductory machine and meter there. Inside the house is already put a switchboard with group machines.
Do I need to put a RCD immediately after the introductory machine?
Installation of a general RCD (difrele) on the input after the meter increases fire safety and protects against current leaks throughout the network. However, this can lead to frequent shutdowns of the entire house when a malfunction in any appliance. It is often more profitable to put individual RCDs on groups (bathroom, kitchen).