Now all of us are more and more aware of this electricity consumption. In addition, since there are always problems with the near-electric water heater, everyone pays special attention to the electricity consumption of the bathroom. Just like the local equipotentiality of the bathroom, a few years ago, they did not pay attention to it at all. Now more and more friends are paying attention to the importance of non-equipotentiality in this bathroom. Now a friend asks such a question: Can the local equipotential terminal in the bathroom be disconnected?
Local equipotentiality in toilet
The local equipotentiality of the bathroom is to connect various electrical devices and other leaking metal objects in the bathroom, or pipes, or other conductive parts, through artificial or natural grounding and copper conductors. The connection is made in order to reduce the potential difference. This is a kind of equipotential bonding.
In the past, some facilities in the bathroom were very simple, that is, a toilet and a washbasin. But now the functions of the bathroom are more and more, and many household appliances have entered the bathroom. For example, common washing machines, electric water heaters, home saunas and electric toilets, etc. Undoubtedly, it adds a lot of hidden dangers to the use of the bathroom. In addition, the bathroom is relatively humid. If the equipotential bonding is not done well, it will have serious hidden dangers for use.
Especially when a person is taking a bath, the skin of the human body is moist, and the impedance will drop when wet. In this case, the voltage that the human body can withstand is about 12V. If it exceeds this voltage, it may cause heart fibrillation and poor blood circulation, especially the blood supply of the central nervous system. People will die from lack of oxygen in a very short period of time. So, this bathroom shower area is a highly dangerous area.
In addition, you may have noticed a phenomenon, such as a bird standing on a single high-voltage line, there is no problem at all, and it will not receive an electric shock. This proves a problem, that is, as long as no potential difference is formed, no current flows. That is to say, as long as an object can be guaranteed to be in a region of equal local equipotentiality, no matter how high the voltage in the region is, then it is good. In fact, the local equipotentiality of the bathroom is based on this principle. It connects all possible conductive appliances to the local equipotential terminal box in the bathroom, and the local equipotential box in the bathroom keeps the bathroom at the same potential, so as to prevent the danger of electric leakage.
There is a dangerous potential in the bathroom, which is the cause of the so-called leakage
The point is that we know that these metal conductors are all conductive. Therefore, it is possible for the bathroom to introduce leakage electricity from other places into the bathroom through metal objects. This is caused by an external leakage current.
The second point is that if the equipment in our bathroom is short-circuited, or the insulation is aging, and the neutral point of the power line is shifted, etc.; at the same time, the leakage protection switch in the distribution box in our home fails, and the ground wire Again there is no reliable connection. At this time, the bathroom where the pipes connected to the equipment are charged will appear, and if people touch it, they will receive an electric shock.
The practice of local equipotentiality in the bathroom
The local equipotentiality of the bathroom is generally used when building a building, that is, during the main construction process, the galvanized flat iron is used for reliable connection with the steel mesh on the ground in the bathroom, and then the galvanized flat iron is reserved for the wall. On the surface, the height is generally 500mm, which is the position where the local equipotential terminal box is installed.
There is a place in the partial equipotential terminal box in the bathroom where the iron can be flattened, and the flat iron can be installed on it. In addition, he has a lot of terminals that are used to connect other objects. In fact, this object mainly refers to two parts: the power PE wire in the bathroom, which is the ground wire; if the lamp in the bathroom has a ground wire, the ground wire should also be led to the local equipotential terminal box in the bathroom. Another is to connect the metal pipes in the bathroom with copper wires that are not less than 4 square meters.
Other problems of local equipotentiality in the bathroom
The first problem is that some people think that the electrical appliances in the bathroom have been reliably grounded through the ground wire, and there are leakage protection switches to protect them. So there is no need to make local equipotential bonding. In fact, this idea is wrong. The protection of local equipotential bonding and leakage protection switch are two different protection measures, and you must not replace them with each other.
The second question is to distinguish between the LEB line and the PE line. LEB lines generally require no less than 4 square copper wires to be buried and laid through pipes. The PE wire requires a copper wire of not less than 2.5 square millimeters. These are two different lines. There are two concepts involved here, one is equipotential and the other is grounding. The PE line is grounded, and the LEB line can be grounded or ungrounded. Its function is that the toilet is at the same potential. If the ground wire in the bathroom is charged, then it can be clamped through the LEB wire at this time, that is, to eliminate the potential difference.
Question 3, this is also a question that many friends wonder about. Everyone is wondering whether lightning will enter the bathroom and cause the bathroom to be electrified? In fact, lightning is a complex process, and the paths taken by lightning are all paths with low resistance. It may lead down wires, or enter the ground along metal water supply and drainage pipes, gas pipes, etc. If the LEB system can be welded to the down conductor, it is possible to introduce a dangerous potential, but this is only possible; but as long as you have done a good local equipotential connection, even if lightning is introduced, there will be no electric shock accident.