Basic and additional potential equalization system. Equipotential bonding box Diagram of additional equipotential bonding system

While studying the issue of power supply for my frame under construction and ensuring electrical safety, I came across such concepts as "grounding", "re-grounding", "potential equalization", "potential equalization". I did not find a clear explanation and delineation of these concepts in one place (maybe I was looking badly), so I will try to understand them in the articles of this site.

I'll start with the potential equalization system.

Electrical installation - a set of machines, apparatus, lines and auxiliary equipment(together with structures and premises in which they are installed) intended for production, transformation, transformation, transmission, distribution electrical energy and converting it into other types of energy (clause 1.1.3 of the PUE).

According to clause 1.7.32 of the PUE potential equalization is an electrical connection of conductive parts to achieve equality of their potentials.

In accordance with the definition of clause 1.7.10 of the PUE "Third-party conductive part - a conductive part that is not part of the electrical installation. " This definition of PUE includes all metal objects larger than 50 × 50 mm in the bathroom. The exact definition of the concept of "third-party conductive part" is given in GOST R IEC 60050-195 "INTERNATIONAL ELECTRICAL DICTIONARY. Part 195: EARTHING AND ELECTRIC SHOCK PROTECTION ": side conductive part - a conductive part that is not a part electrical installation but at which an electrical potential may be present, usually the local ground potential. That is, the belonging of metal parts (objects) to third-party conductive parts is determined, for example, for bathrooms, by the possibility of local ground potential appearing on them.

Potential equalization system (EMS) is designed to equalize the potential of all conductive parts of the building, which include:

structural elements of the building;
engineering networks and communications;
lightning protection systems (if any).

The connection is made with PE protective conductors, which form a "grid" in the building and must connect all of the above parts to the earthing device and earthing switches. In the event of damage in the electrical installation and potential (voltage) hitting the conductive parts of the building, short-circuit currents or large leakage currents occur, which lead to disconnection of the damaged section of the circuit from the power source by automatic switches or RCDs.

Types of potential equalization systems (PFC):

basic potential equalization system (BPCS);
additional system potential equalization (DSPP).

Basic potential equalization system (BPCS)

The basic potential equalization system should consist of the following elements:

ground loop (grounding device);
main grounding bus (GZSH);
protective conductors PE;

The composition of the main potential equalization system according to the PUE

Clause 1.7.82 of the PUE establishes that the main potential equalization system in electrical installations up to 1 kV must interconnect the following conductive parts ( left only what I consider necessary for my home):

a grounding conductor connected to the grounding device of an electrical installation (in a TT system);
a grounding conductor connected to the re-grounding conductor at the entrance to the building (if there is a grounding conductor);
metal pipes of communications entering the building: hot and cold water supply, sewerage, heating, gas supply, etc.
metal parts of the building frame;
metal parts centralized systems ventilation and air conditioning. In the presence of decentralized ventilation and air conditioning systems, metal air ducts should be connected to the PE bus of the power supply boards of fans and air conditioners;
functional (working) grounding conductor, if there is one and there are no restrictions on connecting the working grounding network to the protective grounding device;
metal sheaths of telecommunication cables.

The main grounding bus (GZSh), it is also the PE bus, is installed in the input switchgear (ASU) of the building. The main grounding bus (GZSH) is connected to:

steel strip coming from the ground loop (grounding device);
PEN-conductor of the input line (cable) in the TN-C-S grounding system (PE-conductor of the input line (cable) in the TN-S grounding system).

PE-conductors of group wiring lines, as well as PE-conductors of equipotential bonding of the conductive parts of the building, depart from the GZSH.

In the main potential equalization system (BPCS) it is FORBIDDEN:

Connection of PE conductors to N conductors starting from the main earth bus.
Connect the PE conductors of equipotential bonding with a loop (i.e. in series one after the other).
Install various protection switching devices in the protective PE-conductor circuits (the circuit must not be interrupted).

The connection diagram to grounded structures, elements and utility networks of the building in the BPCS should be radial, i.e. each part of the building to be grounded has its own equipotential bonding conductor.

Additional potential equalization system (EAPS)

An additional equipotential bonding system is necessary to provide additional electrical safety in rooms with increased danger, for example, a bathroom or shower room.

Section 7.1.88. The PUE establishes that all accessible to touch must be connected to the additional potential equalization system:

exposed conductive parts of stationary electrical installations,
third-party conductive parts (i.e. not part of the electrical installation) and
zero protective conductors of all electrical equipment (including sockets).

For bathrooms and shower rooms an additional potential equalization system is mandatory. and should provide for, inter alia, the connection of third-party conductive parts that extend outside the premises. If there is no electrical equipment with zero protective conductors connected to the equipotential bonding system (i.e. with PE conductors, not to be confused with a working zero!), Then the equipotential bonding system should be connected to the PE bus (terminal) at the input.

Heating elements embedded in the floor must be covered with a grounded metal mesh or a grounded metal sheath connected to an equipotential bonding system. As additional protection for heating elements it is recommended to use an RCD for a current up to 30 mA.

It is not allowed to use local equipotential bonding systems for saunas, bathrooms and shower rooms.

Section 1.7.83. The PUE establishes that the additional equipotential bonding system must connect all simultaneously accessible to touch:

exposed conductive parts of stationary electrical equipment;
third-party conductive parts, including touchable metal parts building structures building;
neutral protective conductors in TN systems and protective earth conductors in IT and TT systems, including protective conductors of power outlets.

The specified system consists of the following elements:

potential equalization boxes (KUP);
potential equalization conductors.

The equipotential bonding box contains the PE busbar, which copper wire with a cross-section of 6 sq. mm is connected to the PE busbar of the input electrical panel(apartments, houses). After that, by connecting to the KUP, all metal structures of the bathroom are grounded:

heating;
cold and hot water supply;
bathroom (or shower).

Thus, the protective equipotential bonding conductors from grounded structures are laid with a copper wire with a cross section of 2.5-6 mm2 and connected to the PE bus in the equipotential bonding box. Fastening of protective equipotential bonding conductors to pipes can be done using metal clamps.

Also, all sockets installed in the bathroom are subject to additional grounding.

The issue of ensuring electrical safety and the implementation of an additional equipotential bonding system in bathrooms, showers and plumbing cabins is discussed in detail in Technical Circular No. 23/2009, approved by N.A. Fadeev, Deputy Head of the Federal Service for Environmental, Technological and Nuclear Supervision. (letter dated 08.07.2009 No. NF - 45/2007) and approved by the president of the Roselectromontazh Association, Khomitsky E.F.

The purpose of the circular is to clarify the implementation of a number of provisions of chapters 7.1 and 1.7 of the EIC and specific recommendations for the implementation of individual elements of the additional equipotential bonding system in bathrooms, showers and plumbing cabins and bringing them into line with the new international requirements regulated by the IEC 60364-5-54 standard.

Requirements for conductors of equipotential bonding systems are specified in chapters 7.1 and 1.7 of the "Rules for Electrical Installations" (PUE) of the seventh edition.

However, at present, during the construction of buildings, plastic pipes have become widespread in water supply systems, in connection with which additional questions arose on ensuring electrical safety in installations associated with the likelihood of electric shock from a stream of water, water taps, mixers, heated towel rails and others. metal elements plumbing fittings.

Note

Tap water of normal quality in terms of volumetric electrical resistance (conductivity) refers to semiconducting substances and, from the point of view of the possibility of electric shock, not considered as a third-party conductive part.

When implementing the additional equipotential bonding system in bathrooms, showers and sanitary cabins, the following should be followed:

The additional equipotential bonding system should include:
- all exposed conductive parts of the equipment;
- third-party conductive parts accessible to touch, including metal fittings of the sub-floor, protective sheaths and protective grids of heating cables, outer metal sheaths of equipment of protection class II;
- protective contacts of sockets, bathrooms, showers and plumbing cabins.
When using metal-plastic pipes for the equipment of bathrooms, showers and plumbing cabins, conductive elements of the water supply system (taps, mixers, heated towel rails, valves and other parts made of metal) are considered as third-party conductive parts to be included in the additional equipotential bonding system. In this case, it is recommended to install conductive inserts on the cold and hot water supply pipes and connect them to the additional equipotential bonding system. In this case, the elements of the plumbing system themselves: taps, mixers, heated towel rails, valves and other parts made of metal, do not need to be separately connected to an additional potential equalization system.
In case of use for risers metal pipes and their passage in the plumbing box of the corresponding premises, the installation of conductive inserts is not required, it is sufficient to connect the additional equipotential bonding conductors directly to the metal pipes of the risers.
In buildings where water supply to bathrooms, showers and plumbing cabins is carried out branches in unreinforced plastic pipes conductive elements of the plumbing system: taps, faucets, heated towel rails, valves and other parts made of metal are not considered as third-party conductive parts and not to be included in the additional equipotential bonding system... In this case, the installation of conductive inserts in front of the inlet valve on the side of the riser and their connection to the additional equipotential bonding system is considered a recommended measure. This technical solution provides electrical safety with inadequate quality tap water and / or when replacing plastic pipes with metal-plastic pipes during the operation of the building.
When performing an additional equipotential bonding system in a room, the installation of a special equipotential bonding bus is not necessary. If, during the implementation of the project, for structural reasons, it was decided to install it, then it is recommended to place it in a plumbing box or other convenient place for maintenance.
In individual residential buildings , when device autonomous system sewerage, there is a possibility of drifting the potential of the local land from the side of the sewer. To ensure safety in this case, it is necessary to install a special conductive insert in fan pipe(drain pipe) connected to the equipotential bonding system and / or connect the conductive parts of the sewage storage tank to the equipotential bonding system.
In sanitary cabins, to ensure electrical safety, the protective contacts of the sockets installed outside on the sanitary cabins should be connected to the additional equipotential bonding system, and the luminaire in the toilet separate bathroom must be of protection class II, as in zone 2 of the bathroom.
In buildings where water supply is carried out by branches from an external distribution network (main), the latter should be considered as local land. In case of damage in external power supply networks, made in accordance with the requirements of the PUE of the seventh edition, on the protective PE (PEN) conductor of the installation, relative to the local ground, a voltage of up to 50 V may appear, and in case of damage (breakage) of the PEN conductor of the supply line to values close to phase voltage. When performing a water supply in pipes made of insulating materials, in order to ensure the effective operation of the main potential equalization system, regardless of the quality of the supplied water, provide electrical connection of water to the equipotential bonding system directly at the inlet of the water supply system to the building.
The cross-section of the conductors of the additional equipotential bonding system connecting the PE bus of the shield with third-party conductive parts must be at least half the design section of the PE bus of the shield. If there is electrical equipment in the room, connected by a protective conductor to the PE bus of the shield and included in the additional equipotential bonding system, it is not required to connect the PE bus of the shield to third-party conductive parts with a separate conductor (see clause 7.1.88 of the PUE).
The cross-section of the conductors connecting the exposed conductive parts of electrical equipment and / or protective contacts of the sockets with third-party conductive parts must be at least half the cross-section of the PE conductor of the corresponding power line of the equipment.
The cross-section of the conductors connecting the open conducting parts of the electrical equipment must be at least the minimum of the cross-sections of PE of the conductors of the power lines of the equipment to be connected.
The resistance of the additional equipotential bonding conductors connecting any two third-party and / or open conductive parts accessible at the same time should be no more than calculated by the formula: R = 12 / Ia, where: 12 is the safety voltage level V, adopted for zone 0 bathrooms and shower rooms; Iа is the current value that ensures the operation of the overcurrent protection in a time not exceeding 5 s, in the TN system (in the absence of data, the cut-off current is taken) or the rated residual current of the input device for the differential protection device in the TT system. Note. The use of the TT system is allowed, in accordance with the provisions of clause 1.7.59 of the PUE, in limited cases, in particular, when connecting an individual residential building to air line up to 1 kV, made with bare wires.
According to the conditions of mechanical protection, the cross-section of copper conductors of the additional equipotential bonding system must be at least:
- 2.5 mm 2 - with mechanical protection;
- 4.0 mm 2 - in the absence of mechanical protection;
- it is allowed to use steel conductors with a cross section of at least 16 mm 2.
Connections of the conductive parts of the additional equipotential bonding system can be performed: according to the radial scheme, according to the main circuit using branches, according to the main circuit without branches (connection to a common continuous conductor) and according to the mixed circuit.
In individual residential buildings and other low-rise buildings, in the presence of a single water distribution device (shield), the additional equipotential bonding system is combined with the main equipotential bonding system.

Sewer drains should be considered as a third-party conductive part only in case of blockage.

In buildings where water supply to individual consumers is carried out by branches from an external distribution network (highway), which is typical for most low-rise buildings, the latter should be considered as local land.

In buildings where water supply is carried out by branches in plastic and electrically insulated metal-plastic pipes from a distribution network (main) made of metal pipes and laid outside the building, which is typical for water supply schemes for low-rise buildings, when using water supply and heating systems, consumers may experience leakage currents, exceeding the sensitivity threshold with serviceable consumer equipment. Differential protection devices installed at the input to the installation are insensitive to these currents, since the flow circuit of this type of leakage current is between the PE conductor of the installation (all open and third-party conductive parts) and the local ground. To ensure safety guarantees in this case, the electrical connection of the water supply to the main equipotential bonding system and / or the additional equipotential bonding system should be provided.

In factory-made plumbing cabins, a switch box and a socket are installed outside, which is considered a corridor socket. But except for the developers, no one knows about this, and citizens use them to connect portable appliances in the bathroom. To ensure electrical safety, the protective contacts of the sockets installed outside the plumbing cabins should also be connected to the additional equipotential bonding system.

The protective PE conductor of the outlet line can be considered as an alternative to the additional equipotential bonding conductor only if it is not connected directly to the outlet, for example, through a permanently installed connector block.

Protective measures in electrical installations. Protective measures against indirect contact. Potential equalization

Potential equalization

The electrical connection of conductive parts to achieve equality of potential, carried out for electrical safety purposes, is called protective equipotential bonding.

Protective potential equalization is used in electrical installations up to 1 kV.

According to the PUE, the main potential equalization system in electrical installations up to 1 kV should provide for the interconnection of the following conductive parts:

zero protective (PE) or combined zero protective and zero working conductor (PEN), in the TN system.
a grounding conductor connected to the grounding device of an electrical installation in IT and TT systems;
metal pipes of communications entering the building (hot and cold water supply, sewerage, heating, gas supply, etc.);
metal parts of the building frame, ventilation systems;
lightning protection grounding device;
working grounding conductor;
metal sheaths of telecommunication cables.

All specified parts must be connected to the main ground bus using equipotential bonding conductors.

Additionally, it is necessary to interconnect all simultaneously accessible to touch open conductive parts of stationary electrical equipment and metal parts of building structures, as well as neutral protective conductors in the TN system and protective grounding conductors in IT and TT systems, including protective conductors of sockets.

Potential equalization

Potential equalization is a method of reducing the touch voltage and the step between points in the electrical circuit that can be touched at the same time or on which a person can stand at the same time.

Potential equalization is carried out by electrical connection of metal structures located near the electrical installation with its body (potential equalization), as well as by the formation of a spreading zone by using special grounding devices.

The grounding device, which is carried out in compliance with the requirements for its resistance in electrical installations with voltages above 1 kV, must have a resistance of at least 0.5 Ohm at any time of the year.

Electrical installations with voltages above 1 kV with a solidly grounded neutral are electrical installations with high ground fault currents. These also include electrical installations of 110 kV and above, in which the neutrals of individual transformers are isolated or grounded through resistors or reactors. By reducing the value of the resistance of the grounding device, it is usually not possible to ensure the safety of personnel serving these electrical installations due to the large values of the touch voltage and step voltage obtained during ground faults (to the cases and metal structures of electrical installations). Therefore, grounding in these electrical installations is used with potential equalization.

Potential equalization is carried out by the construction of a loop grounding device on the territory of the electrical installation. This device is a system of electrodes 2.5-5 m long driven into the ground and interconnected by steel strips. This entire system is built in trenches 0.6 - 0.7 m deep and is a metal mesh located in the ground in the area where electrical equipment (E) is to be grounded (Fig. 4.15, a and b).

Figure 4.15 Potential distribution in the current spreading zone (c) when using grounding with potential equalization (a) and (b).

When a ground fault occurs, the current flowing to the ground forms a spreading zone. The distribution of potentials in the spreading zone is determined by the design of the grounding device. For a contour grounding device, the potentials of individual electrodes are summed up, and as a result, the potential of the soil on the territory of the electrical installation is equalized and takes on a value close to the potential of the ground electrode. The current passing through the body of a person who touches the grounded electrical equipment will be determined by the expression (2.10):

and will depend on the coefficient a.

By changing the coefficient a, it is possible to reduce the current in the human circuit to a safe value. The step voltage will also be reduced by using a loop grounding device. An example of the formation of a spreading zone of a contour device is shown in Fig. 4.15, c.

The placement of the grounding grid is determined by the requirements for limiting the touch voltage to normal values and the convenience of connecting grounded equipment. The distance between longitudinal and transverse horizontal ground electrodes should not exceed 30 m, and their depth in the ground should be at least 0.3 m.To reduce the touch voltage on the outdoor switchgear, crushed stone is also added with a layer of 0.1 - 0.2 m thick.

Double or reinforced insulation

The PUE provides the following definitions of insulation:

basic insulation - insulation of live parts, providing, among other things, protection against direct contact;
additional insulation - independent insulation in electrical installations with voltage up to 1 kV, performed in addition to the basic insulation for protection against indirect contact;
double insulation - insulation in electrical installations with voltage up to 1 kV, consisting of basic and additional insulation;
reinforced insulation - insulation in electrical installations with voltage up to 1 kV, providing a degree of protection against electric shock, equivalent to double insulation.

Protection by means of double and reinforced insulation can be ensured by using electrical equipment (tools) of class II or by enclosing electrical equipment that has only the basic insulation of live parts in an insulated shell.

Conductive parts of double-insulated equipment must not be connected to the protective conductor and to the equipotential bonding system.

Ultra-low (low) voltage

It is used in electrical installations with voltage up to 1 kV as protection against electric shock during direct and (or) indirect contact, in combination with protective electrical separation of circuits, or in combination with automatic power off.

Protective electrical separation of circuits

It is used in electrical installations up to 1 kV, as a rule, for one circuit.

The maximum operating voltage of the circuit to be separated should not exceed 500V.

The circuit to be separated must be supplied from an isolation transformer, or from a safety isolation transformer, or from another source providing an equivalent degree of safety.

Live parts of a circuit supplied from an isolation transformer must not be connected to earthed parts and protective conductors of other circuits.

If only one electrical receiver is powered from the isolation transformer, then its exposed conductive parts should not be connected either to the protective conductor or to the open conductive parts of other circuits.

In exceptional cases, it is allowed to supply several electrical receivers from one isolation transformer, while the following conditions are met:

exposed conductive parts of the circuit to be separated must not have electrical connection with the metal case of the power source;
open conductive parts of the circuit to be separated must be interconnected by insulated ungrounded conductors of the local equipotential bonding system, which has no connections with protective conductors and open conductive parts of other circuits;
all receptacles must have a protective contact connected to the local ungrounded equipotential bonding system;
all flexible wires and cables, with the exception of those supplying equipment of class II, must have a protective conductor for equipotential bonding;
protection tripping time in case of a 2-phase short circuit to open conductive parts should not exceed the standardized table. 4.1 time (for IT system)

Insulating (non-conductive) rooms, zones and sites

In cases where in electrical installations up to 1 kV, the requirements for automatic power off cannot be met, and the use of other protective measures is impossible or impractical, insulating rooms, zones and sites are used.

The insulation resistance of the floor and walls of such rooms, zones and sites at any point must be at least:

50 kOhm for installations up to 500 V;

100 kOhm for installations above 500 V.

In insulating rooms, zones and sites, protective conductors must not be provided, and measures must be taken to prevent potential drift onto third-party conductive parts of the room from the outside.

The floors and walls of such rooms should not be exposed to moisture.

When taking protection measures against direct and indirect contact in electrical installations with voltages up to 1 kV, the classes of electrical equipment (power tools) used in the way of protecting a person from electric shock should be taken in accordance with table. 4.2.

Table 4.2. The use of electrical equipment (power tools) in electrical installations with voltage up to 1 kV

Marking	Appointment	Conditions for use in an electrical installation
	When indirectly touched	Application in non-conductive rooms. Power supply from the secondary winding of the isolation transformer of only one electrical receiver
Safety clip - sign or letters PE, or yellow-green stripes	When indirectly touched	Connection of the grounding clamp of electrical equipment to the protective conductor of the electrical installation
	When indirectly touched	Regardless of the protective measures taken in the electrical installation
	From direct and indirect touch	Powered by a safe isolation transformer

A familiar sensation - the antenna is electrifying. Such negative effects arise due to the lack of a potential equalization system. The atmosphere is characterized by its own potential. But we will discuss these amusing questions later. Now let's remember Nikola Tesla, thunder and lightning and brave pilots exploring the clouds.

Why Equalize Potential

Genius creators drew ideas from dreams. Leonardo da Vinci, who slept for an hour and a half a day, in fits and starts, but evenly - every 240 minutes, this was enough. But he stopped seeing dreams, and without this it is difficult to create. There is no information that Nikola Tesla dreamed, although a sea of ideas belongs to his authorship. No wonder the unit of magnetic induction is named after him. He studied atmospheric electricity and realized that it was a curious thing.

According to scientific literature, Earth carries a negative charge equal to 500 kK. Due to atmospheric leakage currents, the charge is theoretically zeroed every half hour. In practice, this does not happen. Scientists have found that fluctuations in the atmospheric current are consistent in time, the maximum charge falls at 19.00 GMT. Mystic? No, the pulse of the Earth.

The charge, constantly leaking into the sky, replenishes the energy of the Sun and cosmic radiation, however, so far the topic has been little studied. One thing is clear: when lightning strikes, the Earth does not lose its charge, but gains. An excess of negative carriers is formed along the perimeter of the cyclone, and an island of positive carriers is formed in the center. At a certain value of the field strength, the negative ring breaks through to the earth's surface, and the planet's potential is replenished.

If the equipotential bonding scheme covered the planet, the bad weather would proceed in a quiet manner. The physics of the process has not yet been determined, scientists suggest the presence of an unaccounted, unknown factor that helps control the weather. In the near future, he will remain behind the scenes. What is important for us is the fact that clouds conceal a potential relative to the Earth, a field strength of 100 V / m. The potential difference between the tip of the nose and the feet is 150 V / m.

We do not receive an electric shock because we are standing on Earth. The potential is equalized electric field deviates upward (lines of force bend). But a piece of metal hanging in the air gradually builds up a charge, leading to unexpected effects. Fortunately, atmospheric current is characterized by units of μA per square meter, and the process is slow. But gradually the metal surface is gaining potential.

If the shield is not grounded in the shield, static electricity is inevitable. The blow is not strong, light biting. But the potential equalization bus is always connected to the screening braid. tv cable to eliminate the described effect. Another measure concerns the antenna circuit. The antenna vibrator is a closed loop, part of which is connected to the braid; additional equipotential bonding is not required. For structures of other types, the problem of equalizing the potentials of each arm is solved separately, but all elements are grounded.

Otherwise, we study the complaints on the network:

I climbed to change the converter to a satellite dish, and it broke in full. Help.
I put my wife to write KVN on the VCR, connect the TV cable, get a discharge.
Plasma panel hums after being grounded according to European standards. It was okay. What to do?
The antenna cable bites.

The readers will easily continue the list. We give the answer in an interrogative form: is the potential equalization box installed correctly? Is the installation done according to the regulations? The cable sheath is a metallic conductive material; according to the norms, it is neutralized on the shields of each floor. According to the rules (RD 34.21.122), the metal parts of the building are connected to the lightning protection bus - the ground loop, where, according to the TN-C-S rules, the neutral wire comes. Within the apartment, the potential is equalized in the bathroom.

How to perform potential equalization

According to RD 34.21.122, potential equalization and equalization is carried out in the ground part with circular reinforcement with an area of 6 and sq. Mm. Requirements meets steel reinforcement buildings, interconnected. The outer loop is laid underground.

Considering the requirements of the standards, cast iron bath should also be connected to an equipotential bonding device, it conducts current and can cause trouble. Please note that the equipotential bonding bars are laid separately from the grounding and zero ones.

Potential equalization

In the switchboard, a bus (part of the main grounding bus) is provided for equipotential bonding, or a KUP is purchased. Inside the equipotential bonding box, there is a common bus for combining conductors, which can be brought to the neutral wire. According to the standard, a single whole is obtained with a lightning protection system, voltage drift. In this case, the structure is supplied with a ground loop of at least two pins (diameter from 10 mm according to RD 34.21.122, but mainly from 18 mm), dug to a depth of at least 3 meters (distance between the teeth is 5 meters). The lightning protection system is united by the foundation reinforcement, reliably grounded. This allows you not to lay an artificial contour. It turns out that, on the scale of a residential area, the creation of a means for equalizing potentials is an art beyond the strength of one person (tenant). On the scale of the apartment, all the terminals are connected to the driveway housing, making sure that the phase is not closed to it. Gas pipes and water supply are not used for this purpose.

Zeroing

The device grounding terminal is located on the body. Do not confuse with grounding! The latter works as long as the plug is plugged into the outlet. To eliminate static electricity, it is important that the equipotential bonding device operates consistently. This is helped by a petal on the bathroom, where the wire eyelet is screwed. Household appliances are equipped with holes on the body, where the wire for neutralization is attached.

Equalization with plastic pipes

According to the rules, at the entrance to the building, the potentials are equalized between the ground, the neutral conductor and the pipes. Modern plumbing is plastic, and this measure has lost its effectiveness. There is nowhere to equalize the potentials.

Arrangement of the system

Sometimes it is required to equip a potential equalization system. This means the removal of step voltage from the floor, the surface of the earth. Protection is needed when there is a likelihood of phase breakdown to the ground. The earth is a good conductor, currents spread inland and over the surface. At high voltages (220 V we do not count) situations arise when a life-threatening voltage drops along the step length. Potential equalization is achieved by laying in the ground, the floor thickness of the grounding fittings.

We type in Yandex "pue 7", click "Search".
We select a site where the document is given in text directly on the page.
Press Ctrl + F, enter the word "equalized" into the search box of the browser - without ending. This will get the maximum number of occurrences.
Scroll through the document with the up and down buttons (near the window), select the appropriate technique.

It is useful to study the types and methods of grounding. We said above, it is permissible to put the potential equalization system in the switchboard on the neutral wire. According to PUE 7, for protection against electric shock, grounding and potential equalization are used both together and separately. The principle is clearly demonstrated by the Soviet household appliances: the power cord is not equipped with a grounding terminal:

How to protect against electric shock through the fireplace body? Connect to potential equalization system.
How to reduce the radiation of an old TV? Connect the housing (metal chassis) to the equipotential bonding system.
How to protect yourself from electric shocks from an old oven? Connect the housing to the potential equalization system.

Strictly speaking, we are talking, rather, about grounding, but this is a secondary issue. The main thing is that the potential of the device case in the house should be the same, preferably zero relative to the ground. With a properly equipped potential equalization system, they do not induce protection against direct contact (at supply voltages up to 25 V AC or 60 V DC). Detailed information is given in the PUE section "Measures of protection against direct contact".

The selection of cables for the equipotential bonding system is similar to grounding: 6 mm square for copper or 10 for aluminum. There are recommendations for steel - 50 square millimeters. But the main potential equalization system works with wire rod with a diameter of 6 mm, and the cross-sectional area is close to 30 square meters. mm, and the conductivity of iron is 5 times less than the conductivity of copper. The installation of the internal equipotential bonding is carried out on terminals with a resistance test, on the outside, mainly with steel and on welded seams with a length of at least 10 cm.

The potential equalization device is divided into main and additional. The first one can be called global, it unites all zero and protective conductors, metal fittings, lightning protection, etc. Additional (SDUP) implies the extension of security measures to a local area. Let's say they combine a cast iron bath, a body washing machine, mixer, connected to zero or protective conductors. Finally, we emphasize that grounding and equipotential bonding are not identical to each other.

Over time, buildings acquire an increasingly wider and more complex electrical system. Thus, consumers with low voltage can receive more damage from overvoltages caused by thunderstorms and arising from the impact of electrical impulses and a decrease in the separation of the dangerous space between electrical objects and the lightning rod. The volumetric system of electrically conductive networks is organized by information supply, antenna structures, district heating communications, water supply, gas and power systems. The only lightning protection when exposed to an electromagnetic pulse is not able to prevent damage to sufficiently weak equipment. Therefore, a network of general lightning protection should be formed, and first of all, the main potential equalization system.

What is it used for

Equipotential bonding is used to ensure equalization in all metal parts of the building connected to each other, that is, to form an equipotential surface. In this case, when an increased potential enters the house on all metal structures, it increases synchronously, due to which a dangerous voltage difference does not develop and arcing and the passage of dangerous currents do not form.

Connecting elements

An important protective measure is the creation of the main potential equalization system. It connects the grounding main bus, the main grounding line, the protective main line and conductive elements, which include:

reinforcing parts of structures with a reinforced concrete base;
metal building elements, climatic systems, centralized heating;
steel pipelines for system power supply.

Most often, the potential equalization system has only one output method. The main busbar is mounted in the distribution element room as close as possible to the insertion point.

Lightning protection system

Due to the rapidity of the current rise and its high strength, a huge potential difference is created during a lightning strike, much higher than that which occurs in connection with a leakage current. Therefore, potential equalization is required to protect against the influence of lightning currents.

To prevent an uncontrolled short circuit, a lightning protection structure, an earthing system, metal equipment, electrical installations with protective mechanisms must be side-by-side or directly combined.

Potential equalization bus with open access for verification work must be connected to the equalizing system. The bus also has a ground connection. V large buildings there can be several of them if they have a connection with each other.

Potential equalization in a lightning protection system is carried out at the point where the conductors enter the room and where safe distances are violated, at ground level or in the basement.

A house built using a steel frame or reinforced concrete base, or with a separate room for external lightning protection, must have equipotential bonding at ground level. In houses with a height of more than 30 m, it is performed every 20 m.

Lightning-conducting parts are installed at a safe distance to prevent the occurrence of impulse reactions. If it is impossible to maintain a safe distance of the equipotential bonding system, the lightning deflection device and the receiver form complementary connections between themselves. It is worth noting that they can lead to the introduction of increased potential into the structure.

Complementary device

An additional potential equalization system is being created, the PUE of which determines the form and application, at the points of location of electrical equipment, in which the existing conditions can be dangerous, and if the standards indicate the need for it. It forms a bond between all pieces of existing equipment and third-party conductors that are next to them.

Typical rooms and facilities in which complementary security measures should be used are antenna equipment, lightning protection facilities, remote communication facilities, areas with high explosiveness, hospitals, fountains, water parks, bathrooms. The company that is engaged in the implementation installation works, should carry out them in accordance with the instructions of the PUE-7.

Lightning protection potentials and rigging

The connection of the lightning protection system and equipment parts should be made, to which the air ducts of climatic and ventilation devices, crane frames, elevator guides, pipelines for systems such as fire extinguishing, heat supply, gas and water supply. If possible, each metal structure connects to equalization buses. Electrically conductive pipes can act as connecting lines (with the exception of a gas pipeline).

If there is an insulated section on the water and gas pipelines, potential equalization conductors are used for shunting. No special connection to the lightning protection device is needed to underground pipelines made of metal located next to the ground. The same goes for railroad tracks. If it is impossible to do without a merger, then it must first be agreed with the operating company.

Earthing

The grounding re-device works with the help of two vertical electrodes with a length of at least 5 m, they are fastened to each other by a horizontal ground electrode. A steel strip acts as the latter; it is also used to form a conductor connecting the GZSh and an additional ground electrode. The strip must be at least 4 mm thick with a cross-sectional area of 75 mm 2. There is no normalization of the resistance of the re-earthing switch.

The cross-section of the supply cable influences the selection of the equipotential bonding conductor; it should not be less than half of the cable cross-section. Most widespread purchased PV1 wiring and a steel strip, a single-core cable is also used. Special clamps are often used when branching the trunk with a wire.

Technical equipment and lightning protection

In accordance with the theses of PUE-7 and observing the boundaries of the conductor cross-section, all connections are made to equalize the potentials of lightning protection structures. Direct connections and those made through spark separation gaps must be separated.

The lightning protection system can be directly combined with the following devices:

earthing elements of the high voltage protection system of security structures;
antenna devices;
ground lines located underground away from communication systems and overvoltage protection;
grounding of power structures, the power of which exceeds 1 kW, while there should be no possibility of entering high potential into the ground electrodes;
protective connections in TT-type networks for protection against electric shock during indirect contacts.

When conducting information or power lines in metal pipes or screening, an additional potential equalization system is not needed.

Spark gaps

Proof tests shall be carried out while gaining access to the spark separation spaces. By correctly designing and installing the internal lightning protection mechanism, damage caused by potential differences and overvoltage surges is minimized.

Connection through spark intermediate separations is carried out for the following elements:

grounding of measuring systems subject to separate design;
installations protected from current leakage and having anticorrosive cathodic protection;
the return wire of the traction element of direct current, as well as alternating current in the absence of the possibility of performing direct connection according to signal and technical reasons;
Auxiliary earthing parts for residual current circuit breakers that operate at hazardous voltages.

Installation

During the construction of the building, the installation of the EMS should be carried out, since there are some difficulties when using it in finished buildings... The additional equipotential bonding box is prohibited for use in buildings with TN-C earthing. If this rule is not followed during a break neutral wire there is a possibility of electric shock to residents who did not install an APS. This restriction applies mainly to the old multi-storey housing stock.

A different type of grounding system allows you to get rid of such a problem: for this, a ground loop is made and connected by copper wiring to the pinching main bus.

Plastic pipes

Today, communications using plastic pipes are quite widespread, for which there is no need to be combined with an equalization system. At the same time, if metal pipes are replaced with plastic pipes with conductive properties in the existing DSPP, there will be a breakdown in the connection between the metal parts in the room (heated towel rail, batteries) and the grounding bus, which makes them dangerous when touched at the same time.

When creating communications using plastic pipes, integration with the equalization system is carried out using metal combs, cranes and check valves to secure the conductors. If there are dielectric inserts in metal pipes, they are added to main system after inserts inside the building.

What you need to know

According to building regulations and norms, today increased attention is paid to the competent installation of the equipotential bonding system. First of all, when the building is put into operation, inspection and verification for compliance with the project is carried out. The creation of an electrical connection of all conductive elements available for touch with the help of special conductors ensures proper electrical safety. The equipotential bonding box in places with a high risk of electric shock acts as an addition.

It should be borne in mind that DSPC can be created only in buildings that have a grounding system with separate routing of N- and PE-type conductors.

A solid metal connection must be established between the parts of the control system if they are connected in accordance with the radial diagram and the required section of the protective conductor.

By the laws of physics each conductor has a specific electrical potential. But by itself it is not dangerous, and the danger is the potential difference between various metal objects. And the higher the difference, the higher the risk of electric shock.

Potential equalization and its purpose

The potential difference can be caused by various phenomena: atmospheric overvoltages, stray currents, static electricity, etc. But the cases of current leakage from electrical wiring through metal objects in the house or the enclosures of electrical appliances are especially dangerous. For example, you are in a bathroom and touching a metal water pipe, you get an electric shock, because the pipe has a different potential caused by current leakage through it due to damage to the insulation of electrical wires in the apartment below.

So, to avoid the possibility of potential differences all metal pipes, housings household appliances, lamps, etc. are connected by metal conductors to each other. As a result of the electrical connection arising between them, all metal objects have the same potential.

But this alone is not enough, it is also necessary to discharge the electric current energy that occurs in unforeseen circumstances safely into the ground, therefore, all metal parts are connected by wires on the grounding bus and, in addition, a conductor from the PE grounding bus of the electrical panel is drawn to it.
If you don't, for example, in the event of a breakdown of insulation and if it appears on the body of the washing machine, then the person will be shocked not by contact with other metal objects, but with any of them, standing on the ground. That is there will be an electrical circuit passing through the human body to the ground. And if all objects are grounded through the PE bus of the electrical panel, then the current will follow the path of least resistance through the grounding conductor. And after a person will pass proportional to its sufficiently large resistance - a safe value of the current.

V apartment building the basic potential equalization system is necessarily carried out during construction. In the basement and on the roof everything metal stairs, doors, pipes, metal structures, switchboard housings, etc. ...
But unfortunately, this connection may be cut off or ineffective according to the laws of electrical engineering due to long distances, therefore, an additional potential equalization system is necessarily made in each apartment.

Potential equalization circuit

Due to the fact that the bathroom is of a particularly dangerous type premises for electrical safety due to humid conditions and the concentration of metal pipes there, it is in it or immediately next to it in the bathroom that plastic box with bus. All conductors connected to a bolted connection or clamp to all metal parts of the bathroom are clamped under the bolts of the grounding bus.

Attention, for each metal object there is a separate conductor from the box - you cannot connect several metal parts in series with one wire. In exceptional cases, only one serial connection can be made, but without breaking the conductor.

Need to connect together separate wires not only for the bathroom body, lamps, water pipes and heating, but also for the grounding contacts of the sockets and the box metal doors in the bathroom.

Usually, box with earthing bus is installed either in the bathroom, but more often in the bathroom behind the sewing of pipes passing there. It, like water meters, can always be accessed through a door in the lining.

According to modern requirements along the interfloor riser with pipes, an additionally grounded strip 50 mm wide or galvanized wire with a diameter of at least 6 mm is conducted, to which the potential equalization box is connected with a separate copper conductor. Thanks to this, a ring is created between the electrical panel and the earthing switch of the house, and this is double reliability.

How to make an additional potential equalization system

The potential equalization system will be easy to make on your own in your private house or apartment, without contacting specialists.
Step-by-step instruction:

That's all done! Check the reliability and tighten all contacts once a year or several years.

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