Potential equalization system

Familiar sensation - the antenna is beating with current. Such negative effects arise from the lack of a potential equalization system. The atmosphere is characterized by its own potential. But we will discuss these interesting questions later. Now we will remember Nikola Tesla, thunder and lightning and courageous pilots exploring the clouds.

Why do we need to equalize the potential?

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

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

A charge constantly flowing into the sky replenishes the energy of the Sun and cosmic radiation, however, until the subject matter has been studied enough. One thing is clear: when struck by lightning, the Earth does not lose its charge, but acquires it. Along the perimeter of the cyclone an excess of negative carriers is formed, and in the center - an island of positive ones. At a certain value of the field strength, the negative ring makes its way onto the earth's surface, and the potential of the planet is replenished.

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

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

If the shield is not grounded in the shield, the discharge of static electricity is inevitable. The blow is not strong, light biting. But the potential equalization bus is necessarily connected to the braided shielding of the television cable to eliminate the described effect. Another measure concerns the antenna circuit. Antenna vibrator is a closed loop, part of which is attached to the braid, additional equalization of potentials is not required. For constructions of other types, the problem of equalizing the potentials of each arm is solved separately, but all elements are grounded.

Otherwise, we are studying the complaints on the network:

• It was useful to change the converter to a satellite dish, and broke it in full. Help.
• I put my wife to write KVN on a VCR, connect a TV cable, get a discharge.
• Humming plasma panel after grounding to European standards. And it was fine. What to do?
• Antenna cable bites.

The list will easily continue readers. The answer is given in the interrogative form: is the potential equalization box installed correctly? Installation is made according to the standards? Cable braid is a metallic conductive material, according to the norms it is zoned on the shields of each floor. According to the rules( RD 34.21.122), the metal parts of the building lead to the lightning protection bus - the ground loop, where, according to the rules of TN-C-S, the neutral wire comes. Within the apartment the potential is equalized in the bathroom.

How to carry out potential equalization

According to RD 34.21.122, equalization and equalization of potentials is carried out in the surface part with round section reinforcement bars of 6 and sq. Requirements correspond to steel reinforcement of buildings, interconnected. The outer contour is laid underground.

Considering the requirements of the standards, the cast-iron bath should also be connected to a potential equalization device, it conducts current and can cause trouble. Please note that potential equalization tires are laid separately from grounding and zero.

Equalization of potentials

In the switchboard, a bus( part of the main grounding bus) is provided for equalizing the potentials or buying the PMC.Inside the equipotential bonding box, there is a common bus for connecting the conductors, which is allowed to run on the neutral wire. According to the standard, a single whole is obtained with a lightning protection system, voltage drift. At the same time, the construction is supplied with a grounding circuit with a minimum of 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 5 meters).The lightning protection system is combined with a foundation foundation that is reliably grounded. This allows not to lay artificial contour. It turns out that, on the scale of a residential area, the creation of a means for equalizing potentials — art that cannot be done by one person( a tenant).On the scale of the apartment, all the terminals on the body of the drive plate are turned on, making sure that the phase is not closed to it. For this purpose do not use gas pipes, water supply.

Zanuleniye

The terminal of zaning of devices is located on the case. Do not confuse with grounding! The latter works while the plug is plugged in. For removal of static electricity, it is important that the potential equalization device is constant. This helps the petal on the bathroom, where the ear wire is screwed. Household appliances are provided with openings on the housing where the wire for grounding is attached.

Equalization with plastic pipes

According to the rules at the entrance to the building, they equalize the potentials between grounding, neutral conductor and pipes. Modern plumbing is plastic, and this measure has lost its effectiveness. Equalize potentials nowhere.

Arrangement of the system

Sometimes it is necessary to equip a potential equalization system. By this is meant the removal of step voltage from the floor, the surface of the earth. Protection is needed when the probability of breakdown phase on the ground. The earth is a good conductor, currents spread deep into and over the surface. At high voltages( we do not count 220 V) situations arise when life-threatening voltage drops across a step. Equalization of potentials is achieved by laying in the ground, the thickness of the floor grounding reinforcement.

We recommend reading EIR 7. A voluminous document, we make the necessary selection according to the scheme:

1. We type “Pue 7” in Yandex, click “Search”.
2. Select a site where the document is shown in text directly on the page.
3. Press Ctrl + F, enter the word “equalized” into the browser search window - without ending. So get the maximum number of occurrences.
4. Scroll the document with the buttons up and down( near the window), select the appropriate method.

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

1. How will it be protected from electric shock through the body of the fireplace? Connect to the potential equalization system.
2. How to reduce the radiation of an old TV?Connect the housing( metal chassis) to the potential equalization system.
3. How to protect yourself from electric shocks from an old oven? Connect the housing to the potential equalization system.

Strictly speaking, this is more about grounding, but this is a minor issue. The main thing is that the potential of the instrument 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 provided in the EIR section “Measures for protection against direct contact”.

Potential equalization cable selection is similar to grounding: 6 millimeters of square cross-section for copper or 10 for aluminum. There are recommendations for steel - 50 square millimeters. But the main potential equalization system works with a rod of 6 mm in diameter, 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 internal potential equalization is carried out at the terminals with a resistance check, predominantly steel on the outside and welds at least 10 cm long.

The potential equalization device is divided into primary and secondary. The first can be called global, it unites all the neutral and protective conductors, metal armature, lightning protection, etc. Additional( SSUP) implies the extension of security measures to the local area. For example, they unite a cast-iron bath, a washing machine body, a mixer, and attach them to zero conductors or protective ones. Finally, we emphasize that the grounding and equalization of potentials are not identical to each other.