Electrical panel in a private home: a complete set of equipment and sequence of connection

Carrying out of private homes connect to an external power supply system, homeowners are faced with various problems and errors:

Performance mismatch induction equipment actual loads on the electrical network;
inadequate electrical home electrical installations, the cause of which - the lack of adequate protection devices against electric shock;
Errors during connection of protective devices and violation of their connection sequence.

It caused all this lack of objective information on how to properly deliver the electricity to the house and what equipment should be equipped with introductory electrical shield.

More precisely, on existing issues, you can find a lot of answers, but not so easy to detect in them accurate information.

PUE Rules for Electrical equipment, building regulations, requirements of local power grid companies - if you delve into it all at once, you can quickly come to a standstill. Therefore, we want to introduce you to the real experience FORUMHOUSE users and the recommendations of experts Legrand group.

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Connecting the power receiving equipment in a private home - this is an issue whose solution should be dealt with by professionals. However, after reading the article, you will be able to take note of a few guidelines for yourself.

Today you will learn:

what is required to design electrical boxes;
what devices must be equipped with electrical plates, and what functions are performed by the installed equipment;
how to ensure the selectivity of home electrical;
how to select a protective device for its performance;
sequence in which to carry out the connection of safety devices (RCDs Emergency circuit breakers, automatic switches (AB)).

Organization of the insertion point

During connection of the electricity metering street shield (CB) located on the discharge support power lines, to distribution box (Distribution board), installed in the room, cable line being (underground or Air).

The shield accounting (CB), frequently, there is only the lead unit and the automatic power metering. The dispensing flap (Distribution board) which is mounted directly in the building, mounted circuit breakers, residual current devices and other elements, which will be discussed below.

In some cases, equipment for CB and Distribution board can be installed in a single housing.

The operating parameters of the equipment installed in the registration plate, and the number of its list - all of which should be written in the draft power (or at least should be calculated profile specialists). But there are requirements that apply directly to the design of the electrical panel.

Sergey Saveliev (CTO Legrand Group in Russia):

The design of the switch box must ensure easy supply of the supply cable, it must include the zero bus and ground bus. In this case the electrical panel must have an internal space sufficient to accommodate multiple outgoing cables, and a margin necessary for possible expansion and modernization installation.

Add that the body panel should be resistant to fire, or be made of self-extinguishing material. At the same time he is obliged to safely protect the built-in equipment from potential damage. Against deliberate damage will help built into the door or flap lock handle, and protection against dust and moisture guarantees specified in the specification IP protection. If the panel will be installed outdoors or indoors where you need extra protection against moisture, dust and mechanical damage, it is best to give preference flaps class IP65 -IK09.

In order to avoid a connection in the course of disputes with experts supply companies (which requirements often contradict each other), together with the architectural project should develop and agree on a draft power.

If the connection point is organized in accordance with the requirements of harmonized electrical design, problems in the process connection and further review by the regulatory agencies in the area of the owner, as a rule, do not arises. Consequently, the work associated with the installation and a complete set of the switch box, will not in vain.

Let's talk about what should be household equipment switchboard.

Main switch and metering device

The starting point is considered a home electrical main switch, which connects the electric meter, and other devices located after the metering device.

Sergey Saveliev:

Denomination introductory AB power-determined, based on the allocated power. For example, when a three phase input and allocated power 15 kW denomination - 25A. When 1-phase input and 7.5kW denomination - 40 A. In this case, if the power of more than 11 kW, the power supply must be three-phase. If there is a project of three-phase three-phase consumers are allowed to connect with the dedicated power less than 11 kW.

reserve input device

If the composition includes a source of electrical autonomous power supply (e.g., diesel) the system must have a reserve input device, which is installed after the accounting unit electricity. We are talking about a switch that allows manual operation to connect consumers to the generator or the external power supply system. This device does not allow to use simultaneously two different power source (transformer substation and diesel). That is its key advantage.

SPD

To protect the electrical installation of high-voltage pulses, from the effects of a direct lightning strike and as a result, from possible fires, the system must be integrated Protection against surge (SPD).

In the general scheme SPDs are arranged immediately after the introductory QF1 apparatus. Moreover, the SPD to be connected to the circuit via a separate QF2 protection device (circuit breaker or fuse). Number of poles incoming unit and SPD should be selected based on the number of phases and the neutral mode. (cm. scheme). If the air entering the building installation of the SPD - is obligatory!

Fire fighting RCD

Fire protective devices designed to protect against fire. As used fire RCD device, triggered by the nominal differential current - 100 to 300 mA. This is a fairly large set point, and it does not allow a person to protect against electric shock. For this reason some groups of consumers are equipped with additional (more sensitive) the RCD.

In recent years, widely used selective fire RCD.

Sergey Savelyev:

Type «S» (RCD selective slow) - is intended to during earth faults in lines (e.g., lines of sockets) It works only downstream RCD particular line, and fire RCD at the continued work by nourishing serviceable parts of the wiring.

Cross-module

In modern power systems often use multiple groups of electrical consumers (female group, lighting and so on. D.). And in order to distribute electricity flowing into the plate between the various groups of input cable, DIN-rail mounting is recommended to install a modular distribution block (Cross-module). Cross-module allows you to enter in one conductor plate, designed for heavy loads, and get somewhat smaller outlet cross-section lines (which depends on the load on a particular group consumers).

In addition, the installation of cross-module provides reliable electrical connections and simplifies the process of connecting additional devices to the existing electrical panel.

RCDs, circuit breakers (AB) for the individual groups

Each consumer line, emerging from the cross-module protects individual machines and RCD. When it comes to their installation in the distribution board, immediately raises two questions:

How to choose the right safety devices at par and residual current cutoff?
How and in what sequence the RCD and the machines are connected to each other?

We will try to give detailed answers to them. First, let's find out what functions are performed by the device presented:

RCD protect people from electrical shock while it can not protect themselves and electrical installation against overcurrents and short circuit currents. Therefore, the power supply system on a mandatory basis should be equipped with both the RCD and AB.
Circuit breakers are also not react to leakage currents, but to protect the circuit against overload and short circuits.

The protective action based on the principle of limiting the RCD (due to rapid shutdown duration) current flow through the human body Accidental touching it to the elements, is under voltage. Under normal conditions, the current flowing in the neutral wire, exactly equal to the current in the phase conductor. If there is a difference between them is due to an earth leakage through faulty insulation or through the human body, the device responds by immediately disconnecting the network.

To understand how a par value should have protection devices, turn to the opinion of the expert.

Sergey Saveliev:

Outlet line (2.5 mm² cable section) protected AB 16A, light line (cable section 1.5 mm²) AB 6 or 10 A. Consumers capacity of more than 3.5 kW are connected to the shield via a separate cable, separate AB. cable section and rating of AV in this case it is necessary to count.

The housing AB always applied letter designation category overcurrent tripping device (e.g., B16, C16). The numeral after the letters indicate the denomination of the device in amperes. In domestic systems use AB the following categories: "B" and "C". Device category «B» are activated almost instantaneously with an increase in current in the circuit up to 3-5 denominations. Device «C» category are designed for instantaneous tripping at 5-10 denominations. Therefore, the machines "B" category are the most sensitive to short-circuit currents and are especially recommended for wooden construction.

Now, as the RCD: these devices are selected on three criteria:

Rated current. Designation prescribed rated current, in amperes, and is applied to the device body. In this case, the letters designating trip category (which are used for marking of circuit breakers or differential automata), on the housing RCD not prescribed.
According to the nominal residual current - RCD main parameter, denoted in milliamps (10 mA, 30 mA, etc...).

By Category leakage currents: the group device - "AC" - work only on alternating current leakage. More sensitive device (group - 'A') - and react to variables and pulsating leakage currents. The simple home systems allowed to use the device group - "AC".

Sergey Saveliev:

30mA RCD to give "headed" group of circuit breakers (e.g., 3-4 are connected to the machine one RCD). Rated current RCD thus should not be less than that of the parent AB (usually higher is the lead-AB).

So, for each RCD can connect multiple AV protecting certain groups of consumers.

If the value is greater than or equal to the RCD nominal superior machine, then to such an RCD you can connect multiple AV (even if the total nominal value of machines will be more nominal RCD). If the nominal value of the RCD less superior AB, then a few machines can be connected to the RCD, only under one condition: if the total nominal value does not exceed the rated current of the RCD.

Simply speaking, the RCD is secure if, before or after the device is included in the circuit AB whose value is less than or equal to the nominal RCD.

And the denomination RCD.

R0c0t (User FORUMHOUSE):

Areas with high levels of humidity (bathrooms, showers) is recommended to protect the differential RCD tripping current - 10 mA, if they are allocated a separate line. In other cases, for example, if one line is highlighted in several rooms (kitchen, bathroom, and so on.. D), should be used RCD with the differential current tripping - not more than 30 mA (PO 31-110-2003).

The sequence of connecting the RCD and circuit breakers

The first rule of the connection: if the phase is taken from one RCD, the zero of all consumers connected to this phase, should be returned to the original RCD. That is, the zero and phase wires should not be after the RCD be mixed with other zeros and phases.

In the diagram, we see two machine guns, going to the lighting group (protection of lighting lines using the RCD is not mandatory). Fire fighting RCD in this figure indicated. Outlet groups are protected Cutout having nominal - 40 A and 30 mA.

The connection is simple:

lighting group is not connected to the RCD, therefore, an offshoot of the zero and phase conductor they performed after induction machine;
the phase on the outlet group is taken from one RCD;
zero receptacle group is fed to a separate zero tavern, which is also connected to the RCD.

During the assembly of electrical panels should avoid situations in which one RCD connects an unlimited number of lines. To ensure this condition standard visor is equipped with several RCDs. RCD in this case are grouped by type of connected premises and load types. For example, a group of rosette bathroom connects to the nominal value of the RCD - 10 mA and outlet group kitchens and living areas are connected to the nominal value of the RCD - 30 mA.

differential automatic

In practice, instead of circuit breakers are often used differential machines.

This device combines in one housing RCD and AB. Emergency circuit breakers apply only makes sense if this device will protect a single line or a single user. If Emergency circuit breakers to protect several lines, each will need an additional set their AB (unless, of course, important to you selectivity of the system, and you do not want to break it).