Features of the electrical wiring for bathrooms

In any modern dwelling there is the number of rooms which constitute the greatest danger in respect of receiving the electric trauma. The norms and rules work in such rooms. Most likely, all already repeatedly heard that the water having high conductivity badly interacts with electricity. Therefore, the norms provided for these rooms, the most strict. It is necessary to observe them carefully. So, it is necessary to deal with all aspects of use of electricity in bathrooms or shower. It is necessary to begin with danger zones which exist there.

Схема электрических зон опасности

Scheme of electric zones of danger.

Danger zones

In bathrooms and shower always allocate four zones of danger. They are established for bathtubs and shower irrespective of the arrangement.

Zone 0

It is the internal volume of the bathtub or the shower pallet.

Zone 1

The zone is limited:

  1. The vertical plane over external sides of the bathtub or the shower pallet.
  2. The horizontal plane at the height of 2,25 m from the floor (or from the bottom of the bathtub or the shower pallet).
  3. Floor.

Zone 2

Borders of the zone are formed:

  1. The external vertical plane of the zone 1 and the plane parallel to it and being from it at distance of 0,6 m.
  2. The horizontal plane which is at the height of 2,25-3 m over the floor.
  3. Floor.

Zone 3

The zone is limited:

  1. The vertical boundary plane of the zone 2 and the plane parallel to it at distance of 2,4 m from it.
  2. The horizontal plane passing at the height of 2,25 m from the floor.
  3. Floor.

Here too it is possible to give additional specifications

Таблица 1. Зоны при стандартном оборудовании.

Table 1. Zones at the standard equipment.

  1. The space located over zones 2 and 3 is considered space out of volumes.
  2. In the presence of the false ceiling without openings in zones 1 and 2 the space which is over it is equated to the zone
  3. And if the false ceiling has openings, then the space over it is equated to the zone 1 or 2.

The space which is under the bathroom or the shower pallet and their boards is equated to the zone 3 if it is closed and access to it is provided through the opening hatch.

Two tables of the arrangement of zones in the bathroom are included below.

The first table is zones at the standard equipment.

The second table is special cases of the arrangement of zones.


Safety of the bathroom is ensured by means of highly sensitive devices. That is all lines giving power supply to the bathroom (lighting, sockets, heating) have to be protected by means of the device of protective shutdown (DPS) of high sensitivity (30 mA).

Safe (low) stress

In this case the power supply network of 12 V at alternating current is used. The lowered tension is received by means of the transformer which is installed out of zones 0-2. The body of devices at the same time should not be grounded.

Classification of electric devices

There is the classification of electric devices by extent of their protection against defeat by the current. This classification was developed on the basis of types of isolation of electric circuits which are the part of the electric device.

There are 4 types of isolation

Таблица 2. Особые случаи расположения зон.

Table 2. Special cases of the arrangement of zones.

  1. The main – isolation of working parts in which malfunctions can cause risk of blow by electric current.
  2. Additional – isolation of separate parts of the design, autonomous from the main isolation.
  3. Double – isolation of all design which includes simultaneous main and additional isolation.
  4. Strengthened – the isolation equal at least double.

The class of electric equipment has to be specified by the producer on the product usually in the form of marking.

There are 4 classes of protection of electric devices

Class 0: this type of the equipment is not allowed to operation any more. It was based on the principle of the main isolation and had no connection to grounding.

Class 1: it is designated by the grounding badge. For this purpose like the equipment protection is provided with the main isolation and connection to grounding of conducting parts. Devices of the class 1 have to be surely connected to grounding of the electrical wiring of your dwelling.

Class 2: one is designated by two squares, in another. This type of the equipment has protection of the main isolation in combination with double or reinforced insulation. The equipment of the class 2 does not demand protection by accession to grounding.

Class 3: it is designated by the rhombus in which there are three lines located vertically. This type of the equipment receives the power supply from low tension in 12 Century. Such devices should not be connected to grounding.

Degrees or indexes of protection

At the choice like electric equipment it is always necessary to consider external influences. Modern standards provide degrees of protection which characterize ability of electric equipment to maintain two main types of external influence:

Таблица кодов IP

Table of the IP codes.

Degree of protection is designated by means of the code from two letters (IP) and two digits.

The letters IP mean the code or the index of protection.

The first digit designates degree of protection against penetration in foreign objects.

The second digit specifies degree of protection against moisture hit.

The table of degrees of protection of electric devices is included below.

Contour of alignment of potentials

Контур выравнивания потенциалов

Contour of alignment of potentials.

There is one more security measure for the bathroom - it is the additional contour of alignment of potentials. Protection is in connecting with each other all conducting elements and the body of devices in zones 1-3 and to connect the line to grounding of the electrical wiring here. The purpose of the action is in balancing the potential of all conducting elements of the room and to avoid various risks of electric shock in case of direct or indirect contact.

The wire of alignment of potentials can be laid by the flush mounting, but at the same time rules of installation of the buried wiring have to be followed. If you decided to make the wire of alignment of potentials hidden throughout, it is recommended to leave open accesses to connections. Communication of metal elements which enter the contour is carried out the wire of 4 mm ² (flavovirent color).

The following elements have to be attached to the contour of alignment of potentials:

Контур выравнивания потенциалов в обычном исполнении.

Contour of alignment of potentials in normal execution.

  1. Openings of controlled mechanical ventilation, if main air duct metal.
  2. Metal armature of floors.
  3. Pipes of central heating and other heating elements (heated towel rail).
  4. Metal frames of doors, windows and ventilating apertures.
  5. Metal pipes for the supply of cold and hot water, withdrawal of the sewerage and gas pipes.
  6. Metal plumbing fixtures.
  7. Electric sockets, lamps (even if they are established on the ceiling and have the metal body).

The example of the device of the contour of alignment of potentials and also examples of fastening of the wire is included below:

Do not neglect installation of the contour at all. Remember that all electric traumas generally happen on negligence.

In conclusion of several councils:

Switches on the bathroom are installed from outer side of the wall.

Sockets are installed in the zone 3 and have to have degree of protection at least IP44 and the protective grounding contact.

Lamps have to be grounded (if have the metal body).

The wires or cables going to other rooms should not pass through bathrooms.

If from the opposite side of the wall on the sites corresponding to zones 0-2 laying of wires, the shtrobleniye is made, the residual thickness of the wall has to be not less than 6 cm.

All lines have to be separate and are protected by OUZO (30 mA).

Use the contour of alignment of potentials to which connect all metal parts which are in the bathroom.

Always carry out connection of electroadjusting products behind the body.

  1. Love

    Thanks, Sergey. And what means — I take in bookmarks. Will you be able to prompt to me and when?

    To answer
  2. Love

    Read attentively, but if it is possible, then "on fingers" since there is no trust to Tajik repairmen. They recognize that they do not know. What or what ouzo should be established to me. One-room quarter. The plate and the oven electric, will be the dishwasher
    In the bathroom stiralka.

    To answer
  3. Sergey

    Everything is clear, I take in bookmarks.

    To answer
    • Andrey

      Sergey - we are glad that this article was pleasant to you.

      To answer
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