2001 year. A familiar master entrepreneur brought a vertical loading washing machine from Germany, which had worked out factory guarantees in a German family, and offered to buy it for neighbors with a significant discount and bonuses: a free installation and its 3-year warranty.

We made an agreement and paid the money. The purchase was placed in the kitchen. For seven months the machine worked amazingly, and then, at the most unexpected moment, it flowed while washing the laundry.

It is good that the hostess was at home and from the remote room I heard the sound of pouring water that filled the floor in the kitchen. In addition, the car "shocked" the hostess when she approached her. Naturally, they flooded the neighbors from below. The called master fixed the malfunction and paid for the repair of two apartments without further questions, and the car still works after this incident. The cause of the leak is simple: during a preventive replacement ...

There is still a scientific debate about how our brain works, but researchers have already come to the conclusion that complex electrochemical processes between cells - neurons - are taking place inside us. For the exchange of information using short electrical pulses. They control all the muscles.

In this case, a person is constantly exposed to the natural magnetic field of the Earth and electromagnetic waves. He has developed protective reactions in his body to such an effect, but they ... are not unlimited.

Over the past two centuries, people have begun to intensively use electricity and the benefits of civilization, not really worrying about their health. But in vain. The effect of electromagnetic radiation (EMR) on the body is constantly increasing, various diseases appear: nervous depression, weakened immunity, problems with the reproductive system, causeless fear ...

Electricity brings many benefits to man. But it is dangerous, especially for children. If an adult already has a certain life experience and knows basic safety rules, then children, especially small ones, only know this world. They are curious, active, agile, and evaluate everything that surrounds them with their senses.

Children examine all the objects around them, touch them with their hands, they can stick them in their mouths, lick their tongue or bite their teeth, chew. In this way they gain experience for later life. However, the human senses are not able to determine the presence of tension, and children do not understand its dangers.

Parents and all adults are obliged to create safe conditions for their life, to teach the accurate handling of electrical appliances. Providing these conditions requires a differentiated, individual approach, taking into account children's age. Toddlers under 3-5 years old are usually ...

Let's first understand in more detail what we will deal with. Let's start with overvoltage impulses. For calculations and the choice of SPD, we need to know what distinguishes lightning current pulses and current pulses of all other overvoltages. The figure shows what their main difference is - the lightning current pulse is almost 17 times longer than the overvoltage pulse, that is, it has a much greater power.

Further, I will list some general recommendations based on the practice of using SPDs: 1. Categorically, circuit breakers cannot be used to protect SPDs from accompanying currents. Only fuses. 2. Class 1 SPD should preferably have a monoblock design (without removable modules). 3. An SPD for a lightning current greater than 20 kA (10/350 μs) should be based on the arresters. 4. The cover in which the SPDs are installed should be metal.Now we will use the SPD selection algorithm presented below. Since when powering the house from VLI we have a grounding system ...

Despite the theoretical possibility of the appearance of pulsed overvoltages with an amplitude of tens of kilovolts in the 0.4 kV power supply system, the REAL value of the amplitude is limited by the pulsed insulation strength of electrical equipment.

The impulse insulation strength of electrical equipment with a nominal voltage of 230/400 volts is set by the standard and is taken equal to 6 kV. Based on this, the appearance of voltages higher than 6 kV in electrical circuits is unlikely (the appearance of amplitudes above 6 kV is possible according to Russian scientists only in 10% of cases).

Based on this, ALL electrical equipment up to 1000 volts was divided into 4 categories (for three-phase systems 230/400 volts): category 4 is equipment that can withstand 6 kV surge voltage (electricity meters, automatic machines, arresters, etc.), category 3 is withstanding equipment ...

Let's start with the simplest. Suppose we have a residential building (cottage) which is powered by a power line (overhead line) and in which metal communications (gas, water supply, etc.) are not connected. We list the dangers that may await us in this case and then how to deal with them.

In case No. 1, a direct lightning strike can destroy the building itself, cause a fire in it, damage the electrical equipment of the house and electrical appliances included in the outlets. In this case, there is only one protective measure - the installation of external lightning protection on the house.

In case No. 2, the TV will fail, possibly igniting it. Protection measures: - installation of the antenna in the external lightning protection zone and / or disconnect the antenna cable from the TV. In case No. 3, a surge voltage of tens of kilovolts is brought into the house, which will cause damage to the electrical wiring insulation and damage to electrical appliances connected to outlets. Protection measures: turn off the power at the entrance to the house at the time of departure ...

TN - C - S system. The diagram shows the minimum necessary kit to protect your home. The ILV relay will protect your home from overvoltage and undervoltage at the input. And if you can not protect yourself from the increased voltage (breaking the PEN wire is unlikely), but what the hell is not joking, and the lower voltage can always occur, which is extremely dangerous for electric motors. In addition, if you have an UZO electronic, then with a reduced voltage or a broken only neutral wire, it may simply not work and leave the house without protection.

The RCD will protect you from direct contact with the phase wire, from leakage currents that can cause a fire, and also instantly turn off the faulty power plant (when the phase closes to its case). The circuit breaker will monitor short-circuit currents and overload in the network. Regarding the re-grounding of the PEN wire. According to the PUE, clause 1.7.61 "... Re-grounding of electrical installations with voltage up to 1 kV ...

Dear Reader! It is necessary to recognize the fact that in the private residential sector and especially in cottages there is an extremely unfavorable situation in terms of electrical and fire safety. Violations are of a large-scale nature.

Particularly depressing is the fact that both professional electricians and electrical engineers themselves sometimes do not understand and do not know certain provisions of the EMP and other regulatory documents. The purpose of this article is to help both electricians and homeowners correctly perform certain tasks.

Consider all the dangers that may lie in wait for people and the house from electricity. 1. Direct contact with the human phase. 2.Short circuit (short circuit) between phase and zero. 3. Damage to the insulation of the phase wire, followed by its shorting to the metal casing of the electrical installation ...