Wiring in the bath: electrical appliances, cable selection, installation rules

For a long time in baths there was only natural lighting - through a small window. With the advent of affordable electricity, conditions have improved markedly. However, wiring in the bath requires a careful approach due to increased humidity and temperature. In the steam room it will be comfortable if there are no extra wires and switches in it, and each lamp has its own place.

Air inlet to the electricity bath

Wiring in the bath is connected from the home switchboard. The cable is laid underground or stretched through the air, which is much simpler. The following rules should be observed.

Electricity is laid over roads not lower than 6 m, and over sections where pedestrians pass - from 3.5 m or more.

Air entry into the building is performed at a height of at least 2.7 m. For this, insulated wires of the SIP series with a cross section of at least 16 mm ^{2 are used} . They do not need a carrier cable. Its role is played by the neutral wire, which can be with or without insulation. The wires are mounted on brackets with anchor clamps. They are difficult to insert into the shield due to their high stiffness. Therefore, outside the building, the wires are connected to a copper cable of the type VVGNG or NUM. It is introduced into the house through a metal pipe, inclined to the street at 5-10 ⁰ . The cores of the input cable are connected to the self-supporting insulated wire using sealed piercing clamps.

Underground cable entry

Underground entry is made by armored cables of the type VBBSHV or VBBSHVNG. Shrinkage of soil and rodents are not dangerous for them. Cross section is from 10 mm ² . The cable is placed in a trench with a depth of 70-100 cm, in a layer of sand. To eliminate the appearance of tension during shrinkage of the soil, laying is done in a wave-like fashion. It is not recommended to use metal pipes to protect the cable, since condensation accumulates in them. It is advisable to use them in the vertical withdrawal of the cable from the ground to a wall or pole.

In the dressing room, a shield is mounted in which the cable is inserted.

Ways to connect electricity

From home, the connection to the bath is usually done single-phase, but it is also possible three-phase. In the first case, current is supplied to the consumer through a phase wire, and goes back along the zero wire. In a three-phase circuit, current flows to the load through 3 wires, and returns one at a time. Some electrical appliances can only be connected using this scheme.

The advantages of a three-phase network are as follows.

1. Power can exceed 30 kW, although this is not required for the bath.
2. Electrical devices with both single and three phase power can be connected.

The disadvantage is the need to install special equipment in the shield. In addition, all phases must be uniformly loaded for the network to work properly.

Wiring Requirements

1. A separate line from the switchboard to the bath should be equipped with a circuit breaker. From it there are cables to lighting devices such as VVGNG and NUM. They can heat up to 70 ⁰ and do not support the combustion process.
2. The wiring in the bathhouse for the steam room is selected with a heat resistance of 170-180 ⁰ (types PMTK, PVKV, RKGM, APPV, etc.). It must not be mounted close to the oven. The heat and moisture resistant cable with silicone insulation is displayed in a box located in a place where there is no high humidity and temperature, and then an ordinary wire is connected to it, which goes to the shield.
3. Hidden wiring is installed, but open wiring is also permitted. In brick walls, it is laid under a layer of plaster. On wooden surfaces it is pulled in corrugated pipes attached with metal brackets. Protection by metal pipes is not allowed due to corrosion.
4. Touching wires with wooden surfaces is not permitted. To do this, all electrical equipment is located on heat-resistant gaskets made of asbestos or ceramics. Insulators are located horizontally in increments of 35-40 cm, and vertically - 2 for each log.
5. The wires for single-phase input are taken three-wire to provide grounding devices.
   

Electrical Requirements

1. Steam room lighting is the only electrical appliance that can be used there, but an electric oven can also be installed.
2. All equipment is selected with a degree of protection against moisture not lower than IP44 (splashproof version). If LED luminaires are used for pools that can be immersed in water, they have a maximum degree of protection IP68.
3. The shield is mounted in a dry room, for example, in a dressing room. It should have a main input, automatic devices and RCDs of 5-10 mA. It is advisable to power the lamps from a step-down transformer.
4. The rules of the PUE require the installation of a temperature limiter in a steam room for an electric heating furnace up to 140 ⁰ C.
5. Luminaires for high temperature are installed with a moisture-proof and heat-resistant lampshade and ceramic holder. The metal parts of the chassis are grounded. Any fixtures used in bathrooms are suitable for washing. The lighting voltage is usually 12 V or 24 V. You can use lights for pools and fountains, which can be under jets for as long as possible or be immersed in water. They work from transformers and have increased electrical safety. Natural light in the steam room is welcome.
6. An electric floor in the bathhouse is required if the coating is made of ceramic tiles on a concrete base. It is mounted in a screed, in a layer of tile glue or on top - in plastic heat-resistant mats. Power is 180-220 W / m ² . Above the heaters are covered with a layer of aluminum foil, which is grounded.
7. Wire connections in the bath are made based on their minimum passage through the washing and steam rooms.
8. Lamps are mounted on walls where the temperature is lower than on the ceiling. The power of incandescent lamps should not exceed 60 watts.
   

How to calculate the wiring?

The calculation of any wiring begins with the determination of the power of all devices. For lighting you need 1-2 kW. About 3 kW will be needed on the washing machine. An electric stove consumes 5 kW or more.

The wire from the house to the opening machine of the bath shield takes up the entire load and its cross section will be maximum (usually 4 mm ² ). Then a separate cable goes to the electric furnace. Its cross section will be slightly smaller than the main one, since the maximum power is consumed (2.5 mm ² ). Separate lines for lighting and sockets with smaller wire sections are also connected. For each of them, its own power consumption and allowable cross section are calculated.

Important! Wiring in the bathhouse should not overload the power supply system in the house. Before installing it, you need to determine how much power the home network will pull.

Electric power

Determining the power is not difficult, since it is indicated on the equipment. The first number means voltage (12 V, 24 V, 220 V), and the second - power, kW. Depending on the size of the total load, the cross-section of the cable conductors is selected. A rough estimate of 1 mm ² cross-section of a copper wire accounts for 10 A load. More precisely, you can determine the tables, which take into account the laying method. For example, for an underground cable, the cross section will be required more than for an air cable . 20% of the power reserve is added to the calculated values. Usually for a bath, a wire with a cross section of 4 mm ^{2 is} taken.

The choice of machines and RCDs

Circuit breakers are used to protect wiring from short circuits and overloads. Automata are selected according to the operating current 10-15% below the maximum permissible value for the wire. They vary by class. For moderate loads, which are subject to house and bath wiring, class C circuit breakers are usually used. A two-pole circuit breaker is placed on the input of a single-phase network , and single- pole on the lines leaving the shield. It is important that the connection is made through a phase wire.

An important device in the shield, necessary for a room with high humidity, is an RCD. It is selected from the standard series, a notch higher in nominal than that of the machine connected in front of it. If the latter is designed for 25 A, then the RCD is taken at 30 A.

Internal wiring device

Wires are laid at the bottom of the walls. A sealed outlet with a cover or switch has an input from below or from the side. With lateral entry, the wires are bent in the form of a knee so that moisture does not flow down them inward.

The wires enter the steam room through the wall, at the locations of the lamps. Their free ends should be with a small margin to conveniently connect to the terminals.

Electrical appliances are grounded if they have metal housing parts. For this, the lead-in cables are selected as three-wire.

All wires from electrical appliances are collected in a shield.

Wiring

1. Drawing up the wiring diagram in the bath.
2. Install the shield. It is needed to distribute electricity to consumers. It is provided with free access, the possibility of ventilation and exposure to high temperature and humidity is not allowed. For ease of maintenance, the shield is installed at a height of 1.4-1.8 m. An introductory circuit breaker is placed in it, to which a gray phase wire and a blue neutral wire are connected. The yellow-green ground wire connects to the protective block, from which the electrical wiring is done. For the bath you need a separate ground loop. Observing the colors, the wires are routed on the machines of the lighting lines, outlets and electric furnaces. On the inside of the flap door, a circuit for the entire electrical wiring of the bath is glued. Each machine is signed for which group of consumers it is intended.
3. Cable routing from the shield. Laying is done only horizontally and vertically. Kinks and twisting are not allowed. Installation is carried out open, closed or combined. An open method involves laying on top of wooden surfaces, through a corrugated sleeve, cable channel or tray made of materials that do not support combustion. On wooden surfaces, strips of insulating materials protruding 10 mm on both sides of the pipe or duct are laid under them. In places of fastening, this must be done. On walls or ceilings, wiring is laid on insulators, rollers, cables or strings. Wire connections are made only in junction boxes. Hidden electrical wiring in the bath is laid only inside the structures, in corrugations or closed boxes (in the wall, in the ceiling, under a removable floor, in the ceiling, inside the structures).
   
4. Connection of fixtures. The body is selected metal, and the ceiling - glass. It is allowed to carry out voltage from 12 V to 36 V in the washing and steam rooms; the wires for lighting are selected with a cross section of 1.5 mm ² .
5. Connecting outlets. They are installed only in the waiting room or rest room. Wire cross section - 2.5 mm ² .
6. Connection of electrical appliances. The heating tank and washing machine are installed in a dry room.

How to choose an electric furnace?

Connection of an electric furnace. The furnace is fenced with a wooden fence with asbestos insulation on the inside. It is selected by power, depending on the volume of the room and the required heating rate. In addition, when buying, you should choose the appropriate dimensions, as well as types: wall, floor, with a steam generator, etc. They cost from 5 thousand rubles. and higher. The cost of electricity for heating is quite large and not all external power networks can provide power of more than 5 kW, for example, for a summer residence. The sauna heater is installed with a direct cable from the shield machine.

Common errors when laying wiring in a bath

1. The location of the wires to the heater and chimney is closer than 0.8 m.
2. Wiring closer than 0.5 m to batteries or pipes.
3. The use of fixtures in the steam room and shower room is below the degree of protection IP44.
4. For wiring at elevated temperatures, a plastic cable channel is used, which quickly deforms from heating.
5. The wiring is located on the ceiling of the steam room. It is especially dangerous to lay it over the stove.

Conclusion

Posting in the bathhouse works under special operating conditions. Elevated temperatures and humidity in the premises require compliance with all electrical safety requirements. With proper design, the right choice of cables with electrical equipment and in compliance with all installation rules, the power supply of the bath will work reliably for many years.