Electricity and electrical appliances are of great importance in our lives, we use them daily and repeatedly, tens and even hundreds of times a day. We are used to doing this without hesitation, forgetting about what potential danger they may pose to humans. But the danger of possible electric shock, fires due to malfunctions of electrical networks, wiring or equipment has not been canceled, therefore, various means are used to prevent accidents . First of all, we are talking about residual current devices (RCDs) and ground loops with the connection of all electrical appliances to them.
Anyone, even poorly versed in electrical engineering, knows that all devices must be grounded. However, not everyone knows what it is and how it is implemented in practice.
Grounding in an apartment building is usually already connected to the switchboard on the landing, and grounding in the apartment is arranged during the installation of electrical wiring. In this case, the third, grounding wire is immediately supplied to all points of consumption, that is, outlets. An outlet with grounding is necessary for almost every modern household appliance. Grounding an electrical appliance - this means connecting its body, that is, the non-current-carrying part, to the ground or to its equivalent. This measure is necessary to prevent electric shock in the event of a phase breakdown on the housing.
In old houses, where the wiring was carried out according to a two-wire circuit, only phase and zero were connected to the devices, there is no grounding in the apartment. This does not affect the performance of the devices, but it is dangerous to leave some devices without grounding, especially those that come in contact with water: a dishwasher, washing machine, boiler, refrigerator, etc.
What to do in a situation if there is no grounding in the shield? Unfortunately, home-grown electricians, having listened to the advice of a familiar "specialist", without any doubt proceed to the grounding device in various ways, often unsafe.
Two ways to not do grounding in an apartment
The most common erroneous way of improvised grounding is grounding on a battery. The attractiveness of this method is understandable, because the heat supply pipes lie in the ground and theoretically can serve to divert the charge. But in practice, the heating pipe can turn out to be ungrounded at any time - for example, at the time of repair or in case of corrosion of the joints. In addition, in recent years, in some sections of the heating plant, part of the metal pipes has been replaced, and the other continues to be replaced by plastic pipes, so you cannot hope for reliable contact between the heating system and the ground. The result of such "grounding" is dangerous, because all conductive objects (even in neighboring apartments) can be energized, and this is kitchen equipment, sinks, bathtubs, etc. There is a danger of mass electric shock, fire.
The next mistake of unfortunate electricians is the connection of the grounding wire to the zero bus in the shield. It is strictly forbidden to do this, especially in cases where the TN-C system (four-wire riser) is used in the house. The danger is that at one point on the neutral wire for a number of reasons there may be a voltage of 220 or even 380 V. Do I need to talk about what happens if you ground the computer or the refrigerator to zero?
Without going into technical details, we can say that the only option that can protect against electric shock in the absence of grounding in the apartment is the installation of special protective devices called RCDs. If it is not possible to ground in the apartment not in a makeshift, but in a professional, competent way, you must use this option.