Anti-freeze cable for water pipes. Heating cable for plastic pipes and its installation

Freezing of water pipes is a fairly common problem in private homes and cottages. They can be buried deeper into the ground, or simply insulated, but at the entrance to the house, in severe frosts, they will still freeze. Experts recommend installing a heating cable for the water supply.

Advantages of a heating structure for water supply:

• If installed correctly and calculated correctly, then throughout the cold weather the water supply will be protected from severe frosts.
• The heating wire can also be installed in drinking water pipes.
• The self-regulating cable can be used both inside and outside the water supply system, outdoors and indoors.
• The self-regulating wire can independently control the heating temperature, depending on the ambient temperature.

The advantages make it possible to freely use water supply in areas of the harshest winters.

The heating cable is designed to maintain the required temperature of sewer pipes and water supply systems that are located on the street. Otherwise, the water pipes will burst.

It is recommended to turn on the heating structure when the air temperature drops to +5. If you wait until the reading on the thermometer drops to minus, the water supply will begin to freeze. It will take more time and energy consumption for heating. While the water thaws, passage will be difficult and the pressure will be weak.

Previously, heating cables were used in industrial plants. It is only now that this heating system has begun to be used in domestic water supply systems.

Heating cables are divided into two types:

• resistive;
• self-regulating.

But the second version of the heating design has more advantages, and therefore is used more often.

Operating principle of the heating element

A resistive cable has a metabolic conductor that heats up when an electric current passes through it.

But, no matter what the air temperature is, +5 or -10, the heat transfer and electricity consumption are the same. For control, a thermostat and temperature sensors are installed in the heating system, as in electric heated floors.

This type of heating cable can be single-core or two-core. A single-core cable is connected to the water supply on both sides. Two-core, on one side, a plug is attached, on the other - a cord with a plug for connecting to a 220 V network.

When laying resistive cable, the wires should not overlap or be too close; when crossing, they will overheat and can quickly fail. And yet, this type of heating cable cannot be cut, otherwise it will simply deteriorate. Therefore, it is settled entirely at any size.

The self-regulating cable heats up the polymer; it is located between two conductors. The more it heats up, the less heat it emits, and when it cools down, the more heat it emits. Thus, it regulates the temperature independently. Due to its properties, this type of heating cable is called self-regulating.

Has the following advantages:

• does not burn out when crossing wires;
• it can be cut anywhere, but you will need to make an end coupling;
• the element can be of any length.

The only drawback of a self-regulating cable is the high price, but if you take into account all the advantages and a service life of more than 10 years, the price is justified.

It is worth considering that pipes with heating cables need to be insulated. Otherwise, to heat the water supply you will need more power and more electricity consumption. Or, in severe frosts without insulation, a flexible heater may not cope with its task.

Methods for installing a heating cable

The heating cable can be installed externally or internally. For each installation method, a certain type of wire is used. Some are intended for indoor or outdoor use only. How the heating element is installed in the water supply is indicated in the technical specifications.

Installing a heating element inside the pipe is recommended if there are no other installation options outside. Usually when the water supply is in inaccessible places.

To install a flexible heater inside, it must meet the following requirements:

• the shell must be free of damage and release of harmful substances;
• degree of electrical protection not lower than IP68;
• Sealed installation of the end coupling.

The transition point to the electrical cord, as well as the coupling, should not be located in the pipe. The wire is not fixed, it is simply tucked inside.

The positive aspects of this method are that with direct contact with water, less electricity is spent on heating the water supply, and it is less problematic to install. It does not require any special fastenings; when repairing, you just need to pull it out of the tee without breaking the ground. There is no need to disclose special structures and insulation materials.

There are disadvantages of the internal method:

• there is less free space in the pipe;
• the element gradually becomes overgrown with plaque, and the passage in the water supply becomes clogged faster.

This installation method can only be used in straight and not very curved water pipes. It is prohibited to pass the heating element through tees or through shut-off valves.

Step by step installation:

1. first, a gland assembly is put on the cable;
2. a tee is placed in the designated place, through which a flexible heater will be introduced;
3. further, it is pushed to the desired place in the water supply, where the water often freezes;
4. After installation, the stuffing box assembly is screwed in and must be sealed.

Outdoor installation

Before installing the heating cable, it is necessary to prepare the pipes. Clean them from dust and dirt, get rid of rust and weld marks. So that there are no irregularities left on the surface. Because it should fit tightly to the walls of the pipes and not be damaged during installation. It is fixed on clean metal every 30 cm, and at least with aluminum adhesive tape or plastic clamps.

If the heater is installed outdoors in the lower part, that is, in the coldest place, then it must be fixed well. To prevent slipping or even the wire may come off. If several wires are installed, then most of them should be at the bottom. And be at a distance from each other if these are resistive models. Under no circumstances should heating wires be interrupted. Another installation method is installation in the form of a spiral. But installation must be carried out very carefully; they do not like sharp or frequent bends.

Installation with a spiral can be carried out in two ways:

1. you need to gradually unwind the coupling and loop it around the water pipe;
2. secure the flexible heater with sagging using aluminum tape;
3. then wrap them around the pipe and secure with a special metallized tape.

If you plan to heat water supply from plastic pipes, then you first need to glue the place where the thread will be attached with aluminum adhesive tape to improve thermal conductivity, and then you can start attaching the heating cable.

More heating material will be spent on tees and various similar devices, because more heat is needed to heat these parts. But it is recommended to ensure that the loops are not too sharply bent when laying.

It is not advisable to use mineral wool for insulation. This material is afraid of moisture and, when wet, loses its thermal insulation properties. After freezing when wet, and then when the temperature rises, the air will disintegrate into small parts. And if the pipeline is located outside, then getting wet is guaranteed.

Insulation materials that will shrink under heavy weights are not suitable, as they will lose their thermal insulation properties. You can use foam rubber as insulation for water pipes, provided that there is no pressure around it. Another option is to put a rigid pipe on top of the polyethylene foam; a plastic sewer model can be used. One of the best options is polystyrene foam insulation, also called shell. It is not afraid of water, can withstand not very heavy loads, and has good characteristics.

Thermostat value

To pay less for heating the water supply, it is better to install a thermostat. In the event that a self-regulating wire is installed. It turns on at +3 and stops working at a temperature of +13.

But if the water is from a well, the temperature in it will not be higher than +13, so it turns out that the cable will work all year, that is, constantly. Although in the summer you can disconnect it from the network, but what to do in the autumn and spring, when the air temperature can suddenly drop below 0 degrees.

There is no need to heat the water that goes into the shower; it will be heated using a boiler.

Conclusion - it is better to install a thermostat; it has a shutdown function above +5 degrees. There will be significant energy savings, and the service life of the heating cable will increase several times.

Quite often, the plumbing system requires repairs due to freezing of pipes in winter. To prevent accidents, heating is used through a cable installed inside or outside the pipe. Additional heating prevents the pipelines from freezing, and it is not difficult to install the heating cable yourself. The photo below shows how a heating cable is laid around a sewer pipe under insulation.

Heating cable laid around the pipe

Cable arrangement

The basis of the pipeline heating system is a heating element located inside an insulating shell that is resistant to external influences. First of all, it must easily withstand temperature changes.

In fact, the pipe is heated through a cable, which has significant differences from the conductors that transmit energy to the load. The heating cable itself is a load. When voltage is applied to it, the passing current generates heat, which is then transferred to the pipe. In Fig. A diagram of heating a pipeline with a cable laid outside is shown.

Diagram of a pipeline heating system with cable from the outside

The system includes the following parts:

• heating - cables with fastening elements (highlighted in red in the diagram and located along the pipes highlighted in blue);
• distribution - power supply cables (dark blue) and information transmission (green), distribution boxes;
• control equipment - protection equipment, starting control, thermal control with air and pipe temperature sensors.

The heating cable is connected to the network based on signals from temperature sensors. When the ambient temperature rises (usually more than 5 0 C), the cable is disconnected.

It is important to choose the right location to measure the pipe temperature. The sensor is usually placed at an equal distance between the turns of the cable.

Advantages of cable heating:

• ease of implementation;
• possibility of equipping any pipeline;
• economical and safe when executed correctly.

Cable types

The most common is resistive cable. It is cheaper and easy to install. The cable is sold with one or two cores. Heating occurs due to ohmic losses in the heating core. If you install the heating yourself, you can use it successfully. It is used for heating water pipes, sewer pipes, and underfloor heating systems. The diameter of the pipes does not exceed 40 mm.

In Fig. Below are single-core (a) and two-core (b) resistive cables. The first one is the cheapest and is best suited for DIY installation. The disadvantage is that the wire must be returned to the voltage source for connection. A two-core wire requires a coupling at the end.

Single-core (a) and two-core (b) resistive cables

Resistive wire is sold in a specific length. If you cut it into pieces, you will have to reduce the supply voltage. Otherwise, the wire will simply burn out from overheating.

When heating containers and pipes of larger diameter, self-regulating cables are used. They consist of two conductive wires. When voltage is applied to them, current flows from one core to another through a layer of electrically conductive plastic, causing it to heat up. The resistance value of the plastic depends on the ambient temperature, which provides significant energy savings due to self-regulation. Its price is much higher, and it is better to invite specialists for installation.

Do-it-yourself water supply with protection

The street water supply on the site can reach a length of several tens of meters. If the water in it turns into ice in winter, repairs can only be done in May, when the ground thaws.

Heating cable outside

The depth of pipe installation is selected based on the freezing level in the region. The indicator is taken as an average and in some cases it is not enough, for example, under a concrete path or paving stones being cleared of snow. In such places, the pipes are laid even lower, otherwise they will have to be constantly repaired due to freezing. The water supply inlet may be close to the surface of the ground or pass through a cold basement. It is advisable to choose pipes from plastic, for example, HDPE. They are cheap and can withstand repeated freezing.

In order to avoid frequent repairs by replacing pipes, it is advisable to lay a heating cable along with them in difficult areas. Buying an expensive heating system does not always pay off. An alternative could be to use an ordinary field worker for communications - P-274. It has very durable insulation that will not require replacement or repair for years when used in the field. The presence of steel wires together with copper wires in the cores creates additional resistance, due to which the cable can be used for heating. In Fig. Below is a cross-section of wire P-274.

Field wire cross-section P-274

For safety, the P-274 field cable is not connected to a 220 V network. It requires a voltage of about 1-1.5 V per linear meter of cable. If we take it 30 m long, a voltage of 36 V will be required. The current will be 8-10 A, and the temperature will reach 60 0 C. This is quite enough to melt the ice in the pipeline. Power can be supplied from a separate unit with a transformer.

For heating, you can even use a regular TRP telephone wire (Fig. below). It can also be used to heat the fittings if the winding is made more tightly.

The use of telephone wire for heating pipes

The field cable is wound externally onto the pipeline in increments of about 10 cm (Fig. below). Since it is cheap, you can also wind a backup cable, since the next pipe repair will not be soon, and the resource of any home-made devices is usually short. Two heaters can be connected simultaneously if the pipe freezes.

Aluminum tape is wound on top, which allows for more uniform heating of the pipe. Aluminum foil provides better heat removal from the cable and does not allow it to overheat when surrounded by insulation.

In regions with cold climates, it is recommended to wind the cable more frequently. As a result, heating efficiency increases. In any case, the length of the spiral must be at least 1.7 times the length of the heated pipeline. If the pipe heating is installed correctly, it can operate in any weather conditions and will not require repairs for a long time.

Application of field cable P-274 for heating water supply

When water pipes are repaired, they should be insulated. On the one hand, the heat from the cable will not go into the ground, and on the other hand, the insulation protects the pipe and cable from the action of the ground.

2-3 temperature sensors are installed in potentially dangerous places in the pipeline. The soldering areas are protected by heat-shrinkable tubes with sealant. The temperature can be controlled automatically or manually.

The heating cable must be connected to power. At a large distance from the shield, a junction box is used. You can install a transformer in it.

More heaters are attached to the fittings, since more heat is needed there.

Cable from inside

If it was not possible to install a heating cable when laying pipes, it can be placed inside the existing water supply. Cable P-274 is resistant to water. The double wire can be unbraided and one core can be passed into the pipe by bending it in the middle. Then there is no need to expose the insulation to create a connection.

The cable is inserted into the water supply through a tee. To enter it, you can use the filter housing. It is important to ensure the tightness of the input. To do this, a fitting is screwed into the tee. A wire is inserted into it, after which the fitting is filled with epoxy glue of the “cold welding” type. In Fig. Below is a section of pipeline with a field cable wire installed inside.

Installing a heating cable inside a pipeline section

There may be no water in the pipeline. It has been experimentally established that at a current of 9 A the cable heats up to 62 0 C in the absence of water. It can remain in this state for a long time.

Internal installation of the heater has the following disadvantages:

• reduction of the passage opening;
• overgrowing of the conductor with plaque;
• Complicating the water supply system reduces its reliability.

Along with the disadvantages, there are also advantages:

• possibility of installation on an existing pipeline;
• minor heat loss.

It is advisable to install a flexible heating cable on straight pipe sections or with slight bends.

If the pipeline is rarely used, for example, in a country house, the water can be drained from it. Then there is no need to turn on the heating cable.

Connection

The heating part of the cable must be connected to the “cold” part. In addition, it is necessary to reliably protect the conductors at the free end of the heater from moisture with heat-shrinkable tubes. The connection to the power cable is made through lugs. The more reliable the connection, the less often the heating cable will require repairs.

Video about connection

You can learn how to connect a self-regulating heating cable with a termination kit from the video below.

To prevent pipelines from freezing, special heating systems of varying complexity are used. To save money, you can install a heating cable yourself, for example, a telephone cable - P-274. The heating system can be made automatic with a thermostat or manually activated.

In regions with cold winters, the water supply may freeze. The consequences will not be long in coming: lack of water in the house and burst pipes will bring a lot of trouble. But there is a way out - a self-regulating heating cable. If you select it correctly from the entire range, it will prevent the water from freezing. It can be mounted both inside and outside pipes.

Heating cable device

Heating cables for water supply systems are far from new. Previously, they were actively used for heating industrial communications. Currently, the use of such systems is widespread in private and communal households, since it is not always possible to lay water pipes below the soil freezing level.

Installation of heating cable for water supply

Self-regulating cable for heating communication pipes, multilayer, consists of:

• two current conductors - copper conductors;
• polymer matrix connecting the cores;
• two layers of seamless insulation;
• copper screen - heat reflector;
• external insulating coating.

The self-regulating water supply heating system also includes a repair kit with parts for sealing the cable when connecting.

Operating principle of a self-regulating cable

The polymer matrix connecting the current-carrying conductors is the main heating element. It is heated continuously. A cable with such “internals” can be cut into separate fragments with a length of 20 cm. The main feature of the matrix is ​​a spontaneous change in heat transfer depending on the external temperature. How it works? As the external temperature increases, the resistance of the matrix polymer increases proportionally, and heat transfer, accordingly, decreases.

Heating cable

The property of self-regulation manifests itself in various sections of the pipeline. Thus, under favorable conditions, the underground part of the pipeline will not heat up, without interfering with the heating of open sections of the pipe by the same cable.

Advice. Such technical characteristics completely eliminate cable burnout due to overheating, and normalize the energy consumption for its operation.

To turn on the heating of the water supply when the temperature drops, simply plug the cable into the socket. Turn on the cable when the temperature drops to +5° in order to be prepared for sudden night frosts.

The heating cable is very easy to use. With proper installation, its service life is unlimited. Reliable overheating protection makes the cable absolutely safe.

Advice. For drinking water supply, the use of such a cable is quite acceptable.

Selecting a heating cable

The choice of a self-regulating heating cable should not be spontaneous. Manufacturers have clearly defined the characteristics of the cable for various conditions of its use.

The first thing you need to pay attention to is the power of the cable. For private homes, a cable with a power of 5 to 25 W/m and higher is used. Moreover, the parameters are determined for each specific case:

• underground water supply with internal heating installation - a power of 5 W/m is quite enough;
• underground water supply with external heating - a cable with a power of 10 W/m is required;
• open water supply - a cable with a power of less than 20 W/m will not cope with heating pipes.

Advice. In private homes, the use of a self-regulating cable with a power above 50 W/m is not advisable. Energy will be wasted, and the cost of such a cable will be considerable.

When choosing a heating cable for a pipeline, such a parameter as operating temperature is always unchanged. Only low temperature ones are used (up to 65°).

Depending on the area of ​​application, the heating cable is classified into food and technical.

Attention! Only food cable can be installed inside a household water supply. Outdoor installation allows the use of any cable.

Installation inside the pipe

A heating cable is often installed inside when the water supply system is already laid and in use, and its thermal insulation cannot cope with low temperatures.

Attention! A cable with a fluorine-containing polymer is laid inside the pipe. It must have a certificate confirming food approval for use.

Entering the cable into the pipe from above does not require any additional clamps, while the bottom connection must be securely fastened to prevent the heater from slipping.

Diagram: heating cable connection

The procedure for installing the heating cable inside the pipe is as follows:

1. Measure the section of the pipeline that needs additional heating.
2. Unravel one edge of the tape (cable) according to the instructions and install the coupling with gaskets for sealing.
3. The second edge of the cable is securely insulated.
4. Place the cable with the insulated edge into the pipes. This must be done with extreme caution so as not to damage the cable insulation.
5. Connect the cable with the coupling to the power supply using a plug or directly to the distribution box.
6. The section of pipe with cable is marked with a bright color inscription.

Attention! Passing the cable through stopcocks and other components is strictly prohibited.

Installing the cable outside the pipe

External installation of a water supply heating system is quite simple. The cable is attached to the pipe with aluminum tape or special adhesive tape according to the following schemes:

The choice of installation scheme depends on climatic conditions and the method of laying pipes. It is worth understanding that the larger the area covered by the cable, the more intense the pipes will heat up.

Before installing the heating tape, it must be wrapped in foil. This way the pipes will heat up more evenly and not waste heat in vain.

The cable fixed to the pipes is again wrapped with a continuous layer of profile tape on top. It will serve not only as cable protection, but also as an additional layer of cable insulation from the insulation.

Attention! The use of plastic tape, as an alternative to aluminum, when installing a self-regulating cable is prohibited.

The pipe with the cable securely fixed is insulated. To do this, use foil, wrapping it tightly around the pipes. The external heating cable is connected to the power supply in the same way as for internal installation.

A self-regulating cable for heating a pipeline will certainly be an excellent solution where it is not possible to ensure reliable thermal insulation of pipes. Its installation will not cause any difficulties. This cable can also be used for additional protection of sewerage and drainage systems or roof heating.

Heating cable for water supply: video

Using a heating cable in a water supply system: photo

It is very difficult to ensure uninterrupted water supply in a country house. Residents of such real estate very often experience freezing of the pipeline in winter. To avoid this problem, when installing a water supply, install a cable to heat the water pipe. Such heating systems protect communications from freezing and destruction.

Laying a pipeline can be done without heating the water supply and sewerage with a heating cable, if the water supply pipes are buried deep enough and have good thermal insulation.

However, in swampy areas and areas close to water bodies, the groundwater level is very high, which often exposes communications to flooding and freezing. If the pipes are not installed deeply and a self-regulating heating cable is laid, then the communications will be reliably protected.

There are also critical areas that are more susceptible to low temperatures - areas where water and sewer pipes enter the house. The heating cable for heating pipes can only be installed in these places.

Such heating systems have very useful features. For example, the possibility of zonal application. That is, from a set of elements you can assemble a small system for heating a water supply in a separate area, without connecting a self-heating wire throughout the network. There are mini-"heaters" of 20 cm, and maxi-"heaters" of 200 meters.

Depending on the type and technical parameters, the heating cable is used to heat pipelines and drains, tanks for collecting and storing liquids in winter. The main task of the system is to protect the liquid from freezing by warming it up through an increase in temperature.

Installation of the heating cable is possible both in a pipe in the ground, that is, internal, and on a pipeline in the open air, that is, outside.

Thus, if you have a choice between connecting a heating cable or not laying a heating system, then you should definitely take advantage of this opportunity and insure your pipeline from freezing.

Design features of the system

The operating principle is based on the ability of a resistive or self-regulating cable to convert electricity into heat energy. The wiring itself does not transmit energy, as is the case with power analogues, it only receives it, and then the wires heat the object, transferring heat.

The heating cable for water pipes consists of the following main elements:

1. One or more internal conductors with high resistance to electric current; the higher it is, the more heat will be generated.
2. The protective shell is made of polymer; insulation in the form of a copper mesh or an aluminum screen is used together with plastic.
3. The outer sheath is made of durable PVC, which protects the inner sheath and core.

Cables for heating a water pipe from different manufacturers differ in alloy, design of protective elements, cost and other parameters.

The most reliable is considered to be a heating wire with a foil screen and several wires. Solid wire is a cheaper option and is suitable for connecting a system in a small section of piping as solid wire transfers less heat.

To improve the characteristics, the copper braid is nickel-plated, and the thickness of the outer PVC sheath is also increased. In addition, the outer layer must be moisture-resistant and resistant to ultraviolet radiation so that the protection can withstand both contact with water and exposure to direct sunlight.

Types of cable heating

The heating cable for sewer and water supply can be one of two types: resistive or self-regulating. Each of them has its own scope of application. So, the first type is more suitable for heating small sections of pipes with a diameter of up to 40 mm, and a self-regulating cable is good for longer sections. Let's look at each type in more detail.

• Resistive has the following principle of operation: current passes through the wires and heats the cable. High current and high resistance contribute to excellent heat dissipation. There are pieces of resistive wire with a constant resistance coefficient. During operation, such a cable gives off an equal amount of thermal energy along its entire length.

Single core wiring is double protected internally and externally insulated. The heater is a single wire that will be connected in a loop-like manner: the wire is connected to the electrical network, then wound around the tube, and then returned back.

A closed loop heating system is usually used for installing “warm floors” and heating roof drains; there is also an option for a plumbing system. Do-it-yourself installation of a heating cable for a water supply system requires double-sided laying of a single-core wire. It is noteworthy that in this case only an external connection is used.

A single-core resistive cable is not suitable for underground installations, since laying a “loop” takes up too much space, and crossing the wiring will lead to overheating.

Wiring with two wires separates their functions: one wire supplies electricity, and the second heats it. The connection diagram is also different: there is no need to create a “loop”, and the cable is connected to electricity at one end, and the other is laid along the pipeline.

The main advantages of resistive cable are its low cost, reliability, ease of installation and long service life (10-15 years). However, there are also disadvantages, among which it is worth highlighting: a fixed length, a high probability of overheating when the wiring is close together, the impossibility of replacing one section and the power cannot be adjusted.

In order not to connect the heating system every time, install a thermostat with a temperature sensor. When the temperature drops below the set value by 2-3 degrees ºC, the thermostat automatically starts the heating device, and as soon as the temperature rises to the set coefficient, the energy is automatically turned off.

• Self-regulating heating cable. This is a universal type of wiring that can be used to heat a roof element, water supply and discharge lines, and containers with various liquids. Such a cable is immediately equipped with a system for adjusting power and heat energy intensity. When the temperature drops below the control value, the system starts heating.

It differs from the resistive model in the presence of a conductive heating matrix that regulates the heating temperature, but with regards to insulation and protection, there are no special differences.

The principle of operation of a self-regulating device is based on the ability to reduce or increase the current, taking into account the resistance indicator. When the resistance increases, the current decreases, which leads to a decrease in power. As a result, the conductor cools down. After the resistance decreases, the current increases and heating begins again.

A self-regulating heating cable for water supply has an important advantage - zonal action. The conductor independently manages his “labor power”: he warms up the cooling areas well and maintains the optimal temperature in those sections where there is no need for strong heating.

The self-regulating heating cable for heating water pipes works constantly, which is very welcome in winter. But when the frosts stop, it is not beneficial for it to always work, therefore, to automate the processes of the conductor, it is equipped with a thermostat linked to the outside temperature. The thermostat for the heating cable will automatically turn off the system when the weather outside is warm enough.

Connection methods: inside or outside?

There are two ways to connect the heating cable: outside or inside the pipe. Each option has special types of wires - for outdoor use and for indoor installation, respectively. The recommended connection method is necessarily indicated in the technical specifications for the conductor.

Insulation of pipes from the inside

Heating cable inside the pipe. To begin installation of the heater inside the water main, it must meet the following important requirements:

• high degree of electrical protection, not lower than IP68;
• protective insulation should not release harmful substances;
• final sealed coupling.

To be able to thread the conductor inside, a tee is installed at the end of the water supply, and a cable is inserted into one of the branches through the gland.

Keep in mind that the coupling - the point where the transition between the electrical and heating wire occurs - must be outside the gland and pipe, as it is not designed to function in a wet environment.

Tees for installing heating wiring inside the water supply can be at different outlet angles - 180°, 120°. 90°. With this connection method, the cable is not fixed at all, it is simply tucked inside.

Outdoor heating pipeline

Installing a heating water cable outside the pipe requires a tight fit along the entire circuit. Before installation on a metal pipeline, their surface must be cleaned of rust, welding marks, dust and other dirt that can damage the wire. The cable is laid on the cleaned pipe and secured with plastic clamps or metallized tape every 25-30 cm.

If up to two threads are stretched, then they are attached at a short distance parallel to each other from below, that is, in the most freezing zone. If there are three or more threads stretching at once, then they need to be positioned in such a way that more wires are installed below, but maintaining a certain distance.

Another option for external connection is spiral. It is necessary to wind the wiring with great care, without sudden movements and many bends. This can be done by gradually unwinding the coupling and at the same time winding the freed wire onto the main line, or simply fix the cable with the slack, and only then lay it in a spiral and secure it with metallized tape.

If the pipeline is made of plastic, then you must first stick a metalized adhesive tape under the wiring, which will improve the thermal conductivity and increase the heating efficiency. Valves, fittings, tees and other connecting elements require more thorough heating. Therefore, when installing, it is better to make several bends at each connection, but remember the radius of the loops.

In this case, it is necessary to additionally insulate the pipeline. Any type of mineral wool is absolutely not suitable for this, since it loses its properties in a humid environment. It is worth abandoning heat insulators that shrink from gravity if you do not use rigid insulation on top.

A shell made of polystyrene foam in the form of fragments with different diameters is the optimal solution that demonstrates high thermal insulation characteristics: it feels good in a humid environment, does not shrink under weight, and reliably protects.

Power and other characteristics of the heating cable

Before purchasing a heating cable, it is necessary to clarify the length of the line that is planned to be insulated, to what maximum temperature the soil freezes and other parameters.

So, when choosing a conductor, you should pay attention to the following characteristics:

• is there a protective braid on the wire that will make the conductor more reliable and provide grounding;
• temperature class;
• type of external insulation;
• power.

For a sewer line, an electric cable with polyolefin insulation is suitable, but for underground water supply it is better to choose a fluoroplastic insulator. For external installation, fluoropolymer is suitable, protecting the cable from ultraviolet radiation and humid environments.

The required power largely depends on the place of residence, since each region has its own low temperature indicators. The choice of power is also influenced by the cross-section of the tubes, the presence of insulation, and the method of laying the heater. The wiring consumption is indicated in a special table in the accompanying documentation for the cable, taking into account the power of the device.

Experience shows that with standard thermal insulation of a pipeline with a polystyrene foam shell (30 mm) in the regions of the central zone of the Russian Federation, to warm up a pipe section 1 meter long, a power of 10 W/m is sufficient from the inside, and a cable with a power of at least 17 W/m is required from the outside. If you live further north, the insulation capacity should increase accordingly.

In winter, private homes often experience interruptions in water supply caused by frozen pipes. Even if water supply lines are installed below the freezing point, there are still weak areas in them, which include the point of entry into the house. The problem can be solved using a heating cable for heating pipes. In this case, communications can be laid close to the surface, and more powerful heating can be organized near the point of entry into the house.

Types of cables

The modern market offers two types of cables for heating pipes: resistive and self-regulating. The work of the former is based on the property of conductors to heat up when current passes. A metal wire is used as a heating element. The temperature of the cable is constant and does not depend on how cold it is outside. It will provide maximum heating and consume the same amount of energy both at -2 ºС and at -30 ºС. To save energy during warming, temperature sensors and heat regulators, similar to those used in heated floors, are installed on resistive devices.

Another feature of resistive heating elements is that during installation they should not be allowed to intersect or be positioned close to each other. This threatens overheating and system breakdown. You need to pay close attention to this during installation.

The manufacturer produces two types of resistive wires: single-core and double-core. The latter are used much more often. This is explained by the fact that in the first, both ends are connected to the electrical network, which is not very convenient. The two-core cable is equipped with a plug on one side, and on the other - an electrical cord with a plug for connecting to an outlet. Resistive elements must not be cut. They are laid completely, even if the length of the wires is much greater than necessary.

Self-regulating heating cables for water supply, unlike resistive ones, are able to change the amount of heat generated depending on the ambient temperature. The electrical conductors in them are intended only to conduct current, and heating is carried out using a polymer material.

This polymer has a special property: when heated, it emits less heat, and when cooled, it emits more heat, which is why the cable is called self-regulating. Such devices have the following advantages:

1. Crossings and contacts of wires do not affect their operation and do not lead to burnout.
2. They can be cut to the desired length, for which markings are applied to the surface of the devices. An end sleeve must be installed on the cut end.

The water supply must be insulated even with any type of heating cable installed. Otherwise, it will require too much heat to heat it. In severe frosts, the cable may not cope with heating, and the water supply will freeze.

Installation Methods

A self-regulating cable for heating pipes can be installed both outside and inside the water supply. For each type of installation there are different types of wires. Some models are designed for outdoor installation only, others for indoor use. The installation method is indicated in the technical characteristics of the products.

Installation inside pipes

Devices intended for indoor installation must meet certain criteria. The requirements for this type of installation are as follows:

• the coating does not emit toxic substances;
• devices have a degree of electrical protection of at least IP68;
• The end coupling is completely sealed.

To install a self-regulating heating cable for heating pipes, a tee is installed at the end of the water supply. A wire is threaded into one of its branches inside the pipe through the gland. The coupling, installed where the electrical wire meets the heating element, should not extend into the pipe and gland, as it is not intended for wet environments. The angle of the tee does not matter, since the cable is not secured, but simply inserted inside.

External mounting

Before installing the heating wire, the pipes are cleaned of dust, dirt and rust. Laying is done on a clean surface. Anything that could damage the device must be removed. The wire is laid along the pipes. It is fixed every 30 cm. Fixation is carried out with metallized adhesive tape or plastic clamps. The cable should be positioned so that it is adjacent to the entire area of ​​the pipe.

If no more than two wires are used for heating, then they are laid at the bottom of the pipes in the coldest place. They are carried out in parallel and at a short distance from each other. If 3 or more wires are installed, then they are placed so that the majority remains at the bottom. The gap between them is strictly maintained, which is especially important for resistive devices.

The wire can be installed in another way, laying the turns in a spiral. This is done by gradually unwinding the bay. Do not allow sharp bends in the cable. You can also first secure the wire with slack, and then wind it and secure it with metallized tape.

If a heating self-regulating cable is mounted on a plastic pipe, then adhesive tape is placed under the wire, which will improve thermal conductivity. On tees, valves and other connecting devices, several loops of wire are made to help protect them from freezing. In this case, you need to make sure that the cable does not bend too much.

Insulation materials

Mineral wool cannot be used for insulation, since when moisture gets in, it loses its insulating qualities. If wet cotton wool freezes, then after thawing it crumbles into dust. Since the environment around the water supply is usually damp, such insulation cannot be used.

Materials that wrinkle under the influence of gravity should be used with caution. When compressed, they lose their insulating properties. Insulation materials such as foam rubber can only be used if the water supply is laid in a specially equipped sewer system. But if the pipe is simply installed underground, then hard materials must be used for insulation. Another option is to put a plastic sewer pipe on top of soft insulation, for example, foamed polyethylene.

A good type of insulation is polystyrene foam, which is produced in the form of pipe fragments. It is sometimes called the shell. This material can withstand loads well, has good thermal insulation properties and moisture resistance.

Required power

This parameter should be given special attention, since it depends on many factors. These include:

• region of residence;
• pipe diameter;
• method of laying the heating cable (internal or external);
• type of insulation.

Typically, each manufacturer provides a table for its products, which indicates how much cable is consumed per 1 m of pipe.

When using medium insulation (expanded polystyrene 30 cm thick), a cable with a power of 10 W/m is required for internal insulation of 1 m of water supply. If the pipe is insulated from the outside, then the heating power should be 17 W/m. These figures apply to central Russia, but the further north the region of residence is, the thicker the insulation and more powerful the heating should be.

The presence of a thermostat

To minimize pipe heating fees, you need to install a thermostat. It is required even if a self-regulating cable is installed. Typically, heating automatically turns on when the water temperature drops to +3 ºС, and turns off at +13 ºС.

But if water is taken from a well, then its temperature will never rise to this value, so the cable will heat it even in the warm season. During the summer months, the heating wire can be turned off, but in early spring and late autumn it is dangerous to do this due to the possibility of frost. There is also no need to heat the water entering the drain tank.

This problem can be solved by a thermostat that sets the shutdown temperature to +5 ºС. Its use can significantly reduce heating costs and increase the useful life of the cable, which has a fixed service life of working hours.

At the same time as the thermostat, you need to install a temperature sensor. It is mounted on a pipe. To prevent the performance from being affected by heating, the sensor must be isolated from the heater.

The thermostat must be installed indoors. A heating cable and a temperature sensor are connected to it. The connection should be made in accordance with the markings on the device. It is better not to buy a device without markings, as its quality is questionable.

The self-regulating heating cable protects the water supply from freezing. It automatically regulates the heat generated; when it warms up, it heats the pipes less, and when it gets colder - more. To prevent the wire from heating the water in the warm season, install a thermostat with a temperature sensor.