The function of grounding and grounding is the same - to protect a person from electric shock. The current-carrying conductor was exposed, current leaked to the electrical appliance case, the socket case was damaged - such a malfunction can lead to unpleasant consequences. The considered protective devices, which are designed to neutralize the dangerous factor, to ensure the safety of a person and his property, will help to avoid this. In the article we will tell you about grounding and zeroing, what is the difference and similarity, we will consider their purpose and installation schemes.

What is the Difference Between Zeroing and Grounding

Zeroing scheme indicating the splitting into N and PE on the terminal block of the shield

It is most convenient to consider the difference between grounding and grounding by the example of connecting household electrical appliances. Modern houses are equipped with three-wire electrical wiring, where the PE conductor is grounding and does not depend on the working zero conductor N. Thus, the body of the electrical appliance, connected to the PE conductor, receives a reliable connection to the ground - grounding.

Old buildings have a two-wire power supply, consisting of a conductor L - phase, N - working zero. N is taken out from the grounding bus in the general house or driveway electrical panel. Initially, it is called a PEN conductor and can be split into N and PE.

The splitting must be done before entering the apartment distribution box, or directly in the box. Further, the PE wire is connected to the body of the electrical appliance in the same way as in the first version, but such a circuit will be called zeroing, since the connection to the ground is not direct, but is carried out through a neutral conductor. Read also the article: → "".

Which system is more reliable

For comparison, you can see several points:

• As practice shows, there are frequent cases of breakage or burnout of the neutral wire in the electrical panel, which makes the zeroing protection system inoperative. In this case, there is a real threat of electric shock to a person. To avoid such a problem, the switching points must be periodically inspected, which creates certain inconveniences.

A burnt-out neutral wire in the switchboard is close to a complete break

• The grounding system is free from these disadvantages, since the PE-conductor does not participate in the general operation of the wiring and is used only when a leak occurs in order to divert the current to the ground.
• The grounding device requires certain knowledge and skills in working with electrical circuits, which in the absence of them also causes some inconvenience associated with the need to call an electrician.

Taking into account the above, we can conclude that the grounding system is more reliable and safe, therefore it is better to use it. However, in the absence of such an opportunity, you can resort to an alternative option. It is forbidden to ground directly in the socket by installing a jumper between the zero connector and the grounding bracket. This poses a threat to humans (electric shock) and to household appliances.

Arrangement of protective current taps when working with three-phase electrical equipment

The switching of three-phase electricity consumers differs from the connection of ordinary household electrical appliances, therefore, the device of protective systems is carried out in a different way. At the same time, it is not necessary to confuse the neutral or ground wire participating in the control system, that is, involved in the start-up and shutdown circuit of the unit, with a protective conductor designed to discharge a dangerous discharge to the ground.

Design, wiring, electrical connection

The work is carried out in several stages:

1. A separate line (track) is arranged along the perimeter of the room, made of a narrow metal strip 40x3 mm or a copper wire with a cross section of 16 mm sq.
2. A bus (preferably copper) with contact devices (pins or holes for bolted connections) is mounted on it in a hidden place. It is allowed to use a metal bus, but in this case, welding the studs is a prerequisite.
3. This line is connected to a ground loop or neutral ground, which is brought out by a separate wire from the switchboard and has a reliable connection to the ground either directly or through a working zero.
4. The housings of all consumers (three-phase electric motors) are connected to the described bus via a copper wire.

In the event of a short circuit from a voltage leakage due to insulation failure or "breakdown" of one of the phases to the body of grounded electrical equipment, the current will immediately go into the ground along the path of least resistance, that is, through a conductor connected to a working zero or ground. This will save a person from electric shock when touching the body of the device. Read also the article: → “ ».

A grounding device is allowed only if there is no possibility of commutation with the ground loop. In all other cases, only protective grounding is considered correct.

The unit is connected through a copper wire to the bus, mounted from the grounding track

Mandatory use of additional protective devices

The described grounding and neutralizing systems are effective in the event of significant leaks or short circuits to the body of electrical appliances. However, in order to achieve complete safety when servicing the equipment, it is necessary to use additional protective means that provide an electrical circuit break in the event of a malfunction.

At manufacturing enterprises, these can be automation units (BKI insulation control or overcurrent protection). But the most common means, both in production and in everyday life, are circuit breakers and residual current devices, which:

• provide a de-energization of the electrical circuit in the event of a malfunction;
• protect the user from electric shock;
• protect the equipment from fire.

These devices can be designed for single-phase or three-phase systems. They are:

• single-pole - installed on one of the lines (zero, phase);
• bipolar - installed on both wires of the electrical wiring;
• multi-pole (three or more) - used with three-phase voltage.

Household wiring diagram with PE grounding conductor and VA and RCD protection

The circuit breaker trips when the current load exceeds the rated value indicated on the device case. The RCD monitors the state of the power grid and trips when the smallest current leakage occurs.

Possible malfunctions of the electrical network and the action of protective devices when they occur

A description of the most common problems arising during the operation of electrical appliances is presented to the attention of users. For the convenience of considering this issue, the information is summarized in the table:

P / p No.	Malfunctions	Protection
1.	Violation of the insulation of the electrical wiring in the wall or ceiling	Grounding (neutralization) RCD
2.	Current leakage to the case due to moisture, contact failure, wire chafing	- / - / -, RCD
3.	Short circuit	-/-/-, Automatic switch
4.	Failure of heating element, engine (phase breakdown to the case, including through water)	- / - / -, VA
5.	Action through the body of the device of current from capacitors of the electronic system	- / - / -, RCD

With the correct arrangement of protective grounding (grounding) and the use of additional means of protection, these factors will not be able to cause significant harm to property or human health. Read also the article: → "".

Installation errors

The most common mistakes in the design of protection systems are the following:

In the absence of special education or skills in working with electrical appliances, it is better to entrust the device of protective systems to experienced specialists.

Questions arising in the design of protection systems

Question number 1. Is it possible to make a ground loop under the windows of a multi-storey building and lay a wire into an apartment?

Theoretically, this is possible, but provided that there is permission from the management company for this, the grounding resistance does not exceed 4 ohms, as evidenced by a certificate from the standardization department, as well as a confirmation from the meteorology department that the device does not violate the lightning protection of the building.

It is possible to ground an apartment in a high-rise building, but it is difficult to document it

Question number 2. Can the water pipe be used for temporary grounding until the main one is arranged?

Nobody can answer this question unequivocally. It is better not to connect the device at all for some time until grounding or grounding is done, but as a temporary measure, you should not endanger yourself and your neighbors.

Question number 3. Is it allowed to bury the metal grounding strip with a plinth or lay in cable ducts?

Can. This will hide the unsightly look and decorate the interior of the room.

Question number 4. Is an electrician from a service organization obliged, at the request of residents, to ground in apartments of old buildings where there is no grounding?

This is not his direct responsibility, but if you approach the issue productively and try to hire him as a specialist, then hardly anyone will refuse additional earnings.

Question number 5. In the driveway, the working zero is brought out from the terminal block, connected to a common zero, emanating from the general house switchboard. Is it possible to remove a neutral wire from a free terminal?

Of course. This will be the same splitting discussed in the article. And in this case it will be done absolutely right. You just need to make good contact and lay the wire very carefully.

In conclusion, we can conclude: You can create a protective system in any case, under any circumstances. The main thing is that it is competently and reliably arranged and the functions assigned to it are effectively performed in full.