The topic that will be considered in this publication will be of more interest to owners of suburban housing or owners of private houses, especially if the building is equipped with a completely autonomous water supply system. water stops flowing. There is nothing to be surprised - if reliable thermal insulation and heating of the water supply system are not provided, one of its sections freezes, ending either with a cork, or with such a significant narrowing of the pipe clearance that the movement of water becomes extremely difficult.

This is not only very uncomfortable from a domestic point of view - the consequences can be much worse. If the freezing process is not prevented or stopped, then with a high degree of probability this can lead to deformation of the pipeline and even to rupture of the pipe body. It all ends in a major accident with the inevitable overhaul water supply systems.

Of course, always when designing a future home and its engineering networks steps are being taken to avoid such a situation. Pipes are buried in the ground below the freezing level calculated for a particular area, prerequisite their thermal insulation becomes reliable. However, in some cases, such measures are simply not enough.

A typical example - the deepening of the trench is simply interfered with by a rocky ridge or any located below reinforced concrete structures. Vulnerable places always remain areas of water intake - the exits of their wells or boreholes, places of tie-in to the city water supply network. Often ice plugs occur in areas where pipes rise to the building, in unheated basements, in places where the basement passes through the concrete mass, etc..

Such sections of the water supply require special attention, and it would be better if electric heating is provided in these places. It is not so difficult to do this, because modern technologies make it possible to use a special heating cable for such purposes.

The principle of heating is based on the conversion of electrical energy into thermal energy when current passes through special heating cables (similar to the operation of a spiral or heating element familiar to everyone). The cable is attached outside or placed inside the pipe in the most vulnerable areas for freezing. The amount of heat released by it is sufficient to maintain such a minimum possible temperature level in the cavity of the pipeline, which should exclude the onset of water crystallization and its transition to a solid state.

It is quite clear that in this case the cable itself must have reliable electrical and waterproofing with a good margin of safety, so that any possibility of rupture, melting, or voltage breakdown on the pipeline is completely excluded.

Currently, the buyer can choose one of several heating cable options:

Resistive heating cables

This type of cable is the simplest in its design. The conductor is made of a certain alloy with high resistance, and when an electric current passes through it, heat is generated.

They are available in single or double strand versions. Single-core in the conditions under consideration are used infrequently - for the simple reason that they require a “loopback" of the circuit, that is, both ends of the cable must converge in one place - at the power source. When heating pipes, this is not always easy to do, but often - and in general impossible.

Two-core cables are more practical in this respect - at one end such a cable is connected to the mains, and at the other end a contact sleeve is installed to ensure the circuit is closed.

The role of a heat source can be played by one conductor - the second in this case serves only to provide conductivity. In some cables, both wires have heating abilities - the power of such devices is much higher.

The conductors are protected by reliable, most often - multilayer insulation, a grounding loop - a screen. The outer layer is made of high-strength, resistant to external influences PVC sheath.

The positive qualities of such cables include:

• High power and overall heat transfer, which is especially important on water pipes large diameter or when in large numbers shaped elements that require heating (tees, flanges, taps, etc. ).
• The relative simplicity of the design, which predetermines and their affordability. So, a similar cable of minimum power can be purchased at a price of 150 rubles per meter.

Resistive cables also have their drawbacks:

• For the economical operation of such a water heating system, it will be necessary to purchase and install additional devices - temperature sensors, control and automatic control units that will maintain the temperature at a given level, including power supply as needed.
• The cable is sold in a certain footage, and the end contact sleeve must be installed in a production environment. Do not cut the cable yourself.

Semiconductor self-regulating heating cables

This type of cable was developed specifically for cost-effective operation, and is fundamentally different in both the device and the principle of its operation.

Two metal conductors are separated from each other by a special semiconductor matrix, which acts as a heat emitter. Special properties used semiconductor provide its maximum conductance at low temperatures, and with their increase, energy consumption is significantly reduced. It is characteristic that a similar process of self-regulation occurs at each specific point along the entire length of the cable. The temperature along the length of the pipe can vary quite a lot, and thus, the maximum heating is carried out precisely in the most vulnerable sections of the pipeline.

The advantages of using such a cable are obvious:

• Significant savings are achieved in terms of energy consumption. If the overall air temperature rises, the system will immediately react with a reduction in power consumption.
• Such a cable can be purchased in any length - most of its varieties have places cutting with a step of 200 or 500 mm.

The main disadvantage of such a water supply heating system is the rather high price. So, even the most inexpensive types can cost about 300 rubles per meter, and the upper limit of the cost "goes off scale" even for 1000.

The water supply heating system may involve the external installation of the cable or its placement in the pipe cavity. Each of these technologies has its own characteristics, which is taken into account when selecting desired model and when doing work.

Heating cables can be produced with a round cross section, but for external placement on a pipe, a flattened (tape) shape is better suited, which will more contact with the surface and more efficiently give thermal energy. The power range is also quite wide - from 10 to 60 watts per running meter- this should be taken into account when drafting the heating system, taking into account the material of the pipes and the specific conditions for the location of the water supply.

There is a rather complicated system for calculating the required power, which is used by specialists at the stage of drafting projects. However, simplified. AT living conditions, you can use the following parameters:

If it is planned to heat the pipeline with the placement of the cable inside, then a specific power of 10 W / m will be sufficient for this.

When the cable is placed externally on metal or polymeric water pipes, the following indicators are based on:

— ؽ÷¾inch–17 W/m;

— ؾ÷ 1½inch–27 W/m.

More powerful heating cables or tapes (e.g. 31 W/m) are used in private construction for heating sewer pipes with a diameter of 100 mm and above.

The delivery set of the water supply heating system usually includes the heating cable itself and the “cold” part - the wire for switching with the power source. The "cold cable" may already be connected to the heating part, but more often this work has to be done independently. In this case, the kit may include tubular terminal adapters and required amount heat shrink tubing of various sizes. In the case of using a self-regulating cable, in addition, there must be a special end sleeve that reliably insulates the cut end.

Video: one of the sets of heating cable for plumbing

A temperature sensor with an automation unit (thermoregulation) is almost never included in the kit - they will have to be purchased separately. Thermoregulation units are available in various designs - for example, they can be similar to wall-mounted floor heating thermostats, installed in an electrical panel on a DIN rail like a conventional machine, mounted directly on a pipe in a place convenient for maintenance and control.

For self-regulating cables, compact temperature controllers are produced, which are placed on the "cold" part of the cable, pre-configured to turn on the power when the temperature drops to 5 ºС and turn off when it reaches 15 ºС.

"Cold" wire with installed thermostat

Arrangement of a water supply heating system will require the installation of a separate machine, with an estimated power of about 25 amperes. The emergency protective device system - RCD will never become superfluous.

Installation of a water heating system

The most important operation is the connection of the heating cable with the power cable

The cable is sold most often by the footage, that is, the required amount is purchased to warm up a specific section of the pipe. Before starting installation, the integrity of the cable insulation along its entire length must be checked again. Neither in In no case is it allowed to lay a cable with signs of surface damage.

One of the most important operations is switching the heating part of the cable with the “cold” one, if it was not provided by the manufacturer or this service is not provided by the store. Each of the models may have its own specific connection features, which must be reflected in the instructions attached to the kit. The main task is to ensure reliable electrical contact and, at the same time, create a multilayer insulating protection that completely eliminates the possibility of a short circuit and voltage breakdown to the outside.

For example, let's consider step by step how the cable is prepared for further laying on the water supply system.

Step-by-step instructions for preparing the heating cable for further installation

Illustration
	When buying the required cable footage, you usually immediately purchase the appropriate kit for connecting to the power cable and insulating the free end. The kit includes heat shrink tubing different diameter and length, crimp sleeves that will play the role of connecting terminals. Heat shrinkage for such purposes is used special, applied to inner surface a layer of glue - this dramatically increases the insulating qualities of the resulting joints. In many kits for insulating the free end of the cable, it is provided not with a conventional heat-shrinkable tube, but with a ready-made sleeve, already plugged at one end (as in this example).
	After the required cable length has been measured and cut, you can proceed to work. It is most convenient to do this not “on the knee”, but on a workbench. From the end of the heating cable, which will be connected to the power cable, the outer insulation is carefully removed, at a distance of 45 mm from the edge. A neat incision is made around the circumference with a knife ...
	... then - a longitudinal incision, and the upper dense insulation in this area can be easily removed. There may be a ground shielding braid underneath - if the cable is equipped with one. In our case, there is no connection to the ground loop, so the cable was chosen without a braid. If it is, it is carefully cut off with wire cutters. In the same case, when switching is also planned for the ground loop, the braid is assembled into one neat pigtail and is bent to the side for the time being.
	Under top layer insulation, another one will open - thinner translucent. It is also carefully removed.
	The heating matrix is ​​carefully cut with a knife in the center, not reaching about 5 mm from the end of the stripped section
	Heat shrink tubes are put on the disconnected halves.
	Pay attention - one of them is about 15 ÷ 20 mm shorter than the other. This is necessary to spread the length of the connection of the two wires of the cable.
	By using building hair dryer the tubes are heated, deposited, tightly fitting the insulated sections of the wires.
	The ends of the wires are trimmed - each of them should protrude from their heat shrink by about 9 ÷ 10 mm.
	The conductor is cleaned from the remnants of the matrix. To do this, first a neat incision is made along the circumference, and then the incised "cylinder" can be easily removed progressively along the wire.
	The illustration shows the stripped wires of the cable well. A crimp sleeve is alternately put on them.
	Then it is crimped - using side cutters, pliers or a special crimp. It immediately makes sense to check the quality of the contact - the wire must be securely fixed in the sleeve, without the slightest backlash.
	This is what the sleeve should look like after crimping on one side.
	Exactly the same operation is carried out on the second wire of the heating cable.
	After that, pieces of heat shrink tubing are put on the ends of the wires with crimped sleeves.
	Go to the "cold end" that is, to the power supply cable. A section of external insulation is removed by about 40 mm, the ends of the wires are stripped by 8 ÷ 10 mm.
	On the power cable, they are sequentially put on and so far two pieces of large-diameter heat-shrink tubing are laid aside. First, the one that is longer is put on ...
	... and then a shorter one.
	Since in our case, grounding is not assumed, the yellow-green wire simply bites off. In the event that the shielded heating cable will be connected to the ground loop, this wire is temporarily bent to the side for the time being.
	The stripped end of one wire is inserted into one of the sleeves installed at the end of the heating cable, crimping is performed. Moreover, such wiring begins with a shorter wire of the heating cable.
	A similar operation is carried out with the second power wire. Its length is already precisely cut in place (it is clear that it requires a slight shortening), and then the end is stripped.
	Then everything is the same - the stripped end of the wire is inserted into the sleeve and crimped.
	The wires are connected, but now it is necessary to ensure their reliable isolation.
	To do this, the previously put on pieces of heat shrink tubing are shifted so that they are located in the center of the connection nodes, completely closing them on both sides.
	Next, they heat up with a hair dryer for tight shrinkage of the tubes.
	The next step is to shift the previously put on a piece of wide heat shrink (shorter) to the commutation area.
	It must completely cover it - all the way from the removed outer insulation of the heating and electrical cables.
	Heating and shrinkage of this area is being carried out. The tube should tightly wrap all connections located under it, creating a common "cocoon". By the way, it is after this that, if necessary, switching of the ground loop with a shielding braid can be carried out. The connection is carried out in the same way - using a crimp sleeve and closing this node on top with a small piece of heat shrinkage of small diameter.
	After that, the entire resulting assembly is completely closed with a second, longer piece of large diameter heat shrink tubing.
	Warming up and final sealing of the cable connection is carried out. Since heat shrink has an adhesive layer inside, when heated, small droplets of glue can come out from the ends. This is a completely normal phenomenon, speaking only about good quality created isolation node.
	The finished switching unit for heating and electrical cables should look something like this.
	Now it's time to insulate the free end of the heating cable. In our case, a ready-made plug-plug will be used for this, but it is quite possible to get by with a heat-shrinkable tube with an adhesive inner layer. To ensure complete safety and reliability of the insulation, it is recommended to slightly space the cut ends of the two conductors of the heating cable along the length. To do this, one conductor is cut with a “step”, that is, it is made shorter than the other by 7 ÷ 10 mm.
	Next, the end sleeve is put on. This, in fact, is also a heat shrink tube, but only with an already plugged end. If conventional heat shrink is used, then it is put on in such a way that in addition to 45-50 mm put on the cable, about 30 mm remain free, that is, they go beyond the cut end.
	Further - everything is in the usual order - the worn clutch is heated with a hairdryer.
	When heated, the sleeve settles and creates a reliable insulation at the end of the heating cable. If a tube is used, then after heating and shrinking, its section protruding beyond the cable boundaries is carefully crimped with pliers to a width of about 12 ÷ 15 mm. The remaining excess tube, so that it does not interfere with the installation of the cable, can be cut off.
	Everything, the preparation of the cable for further installation on the plumbing system is completed.

Another example of cutting a cable and connecting it to a power wire is shown in the video below.

Video: how to properly switch a heating self-regulating cable

When watching a video, be sure to pay attention to the correctness and reliability end sleeve installation.

Cable installation over a water pipe

• The usual location of the cable is along the pipe in one line. It is never placed on top of the pipe. This is done for two reasons. Firstly, the possibility of damage to it with a possible mechanical load on the pipeline from above (falling objects, tools, etc.) should be excluded. Secondly, the liquid always freezes from below, and it is this section that needs maximum heating.

• If one cable is not enough for reasons of the required heating power, several “threads” are launched, arranging them as shown in the diagrams:

• They do it differently - they lay one cable in a spiral around the pipe. This can also be done in different ways:

- Simply winding the pipe with a cable with a certain pitch;

- This is not always convenient, and in some cases it is simply impossible, when the space for work is limited, and there is no way to pass the entire coil of cable under the pipe. Then they act differently: they leave loop allowances with their subsequent wrapping around the pipe body in the opposite direction.

• How to fix the cable to the surface of the pipe? If polymer pipes are used for plumbing, then without options - only with aluminum tape, which will ensure maximum heat transfer from cable to pipe. In this case, the cable is fixed along its entire length.

At the same time, in particularly problematic areas, heat transfer can be increased by gluing the contact area with aluminum adhesive tape or even completely wrapping the pipe in foil even before laying the cable.

• When installing the heating system on a metal pipeline, the cable is fixed in a ring way with a certain step between the attachment points (no more than 300 mm). In this case, it is recommended to use heat-resistant adhesive tape or a special plastic cable bandage.

There are features of cable laying at some water supply units:

• When placing the cable on bends, it should be as close as possible to the outer radius of the bend.

• A lot of heat is always removed at the points where the pipe is attached to metal supports. These sections will require an additional loop at the bottom - as shown in the diagram.

• Particular attention is always required by massive water supply units - taps, valves, flanges. It also requires cable laying according to a special scheme - see figure.

• The next important issue is the placement of the temperature sensor. In no case should it be placed in close proximity to the heating cable, otherwise the entire control system will simply lose its meaning, since the sensor must take temperature readings as accurately as possible inside the pipe. Approximate diagrams of its location are shown in the figure.

Place of the sensor when laying one cable ...

... two ...

... or even three

• Under the sensor, the surface of the pipe must be glued with aluminum tape, and with it it is fixed at the installation site. Usually, the coldest place in the pipeline is chosen to install the sensor.

Installation of the heating cable inside the pipe

In some sections of the pipeline, it is simply impossible to install a cable over the pipe, for example, in sections passing through floor slabs, a plinth, concrete rings of a well and etc.., the technology of installing the cable inside the pipe will come to the rescue.

To do this, they acquire, which can be used in such conditions - with especially reliable insulation, round cross-section. The kit should include a special gland assembly - threaded bushings and washers with a conical or cylindrical rubber seal placed between them.

• Before starting the installation of the cable, all plumbing equipment is immediately put on it in the required sequence, in accordance with the instructions, and only then does the connection with the “cold” wire take place.
• At the point where the cable enters the water supply, a tee is installed into which the sealing sleeve is screwed.

• Then the cable is very carefully inserted into the body of the pipe to a predetermined length. It should be taken into account that in this way only straight sections of pipes or those with minimal bends are heated, which will not interfere with the free passage of the cable. Neither in In no case is it allowed to pass the cable through valves, taps, latches, or connection points where protruding threads inside can damage the integrity of the insulation.
• After the cable is inserted, the gland assembly is completely twisted and crimped to prevent depressurization of the plumbing system.

An example of installing a heating cable inside a water pipe - step by step

Illustration	Brief description of the operation to be performed
	AT this example the installation of a water supply section from HDPE pipes will be considered. House - on pile foundation, the well is located directly below it, that is, the section of the water supply between the heated room and the ground level, as well as going to the well to the entire depth of freezing of the soil, needs to be protected from freezing. In this section, there is a need for two turns at an angle of 90 degrees - this will impose some changes in the process of installing the pipeline and cable in it. To begin with, the heating cable entry assembly is assembled. A regular 1" brass tee is used. Two fittings for HDPE pipes and a penetration unit will be connected to it. In the first illustration - "fitting" of all components of the node. A HDPE fitting is screwed onto the tee
	The second fitting is sampled (at a 90 degree angle to the first). And now, an adapter from 1 inch to ¾ is placed on the remaining outlet of the tee - to assemble the input unit.
	The next step is to put an adapter from 1 inch to ¾ on the remaining free outlet of the tee - for further assembly of the input unit.
	A bushing is screwed into the adapter, in which the sealing assembly will be located.
	This sealing assembly itself consists of several parts. From below, it rests on the washer - shown by an arrow.
	Above is a sealing ring-shaped rubber sleeve with a hole in the center, through which the heating cable will be passed.
	For uniform crimping of the rubber coupling, another metal washer is installed on top of it.
	And the final “packing” of this sealing assembly itself will be carried out by tightening the clamping nut.
	Here is the entire tee entry unit of the heating cable assembled "dry" - to check the condition of the threaded connections and completeness. Now you can proceed to further installation - already with the sealing of the joints.
	For mounting a plastic fitting into a brass tee, it is quite possible to use FUM tape. It is wound in several layers on the threads, and the tatem fitting is screwed into the socket of the tee and tightened with a wrench.
	The second fitting is mounted in the same way.
	Seal threaded connection two brass parts - a tee and an adapter, it is still better with the help of winding from tow with a coat of Unipak type sealing paste.
	The assembled tee with its "hinge" is still removed to the side. On the cable from the side of the end insulating sleeve, the parts of the sealing assembly begin to be “strung”.
	Put them on, of course, in reverse order. The clamping nut is put on first.
	Next comes the brass washer.
	Difficulties can arise when pulling the cable termination through the hole of the sealing rubber sleeve - simply because of the increased thickness of the insulation at the end. But this will have to be done with effort and, of course, with some caution. If the work is carried out in cold weather, you can slightly soften the rubber sleeve by warming it in warm water. Eventually, the rubber will give way and the clutch will go into the hole.
	To make it possible to apply force to pass the end sleeve through the rubber bushing, you can rest the seal against the jaws of the adjustable wrench, as shown in the illustration. As soon as the rubber sleeve passes the insulating sleeve, it can be moved further along the cable, although not quite freely, but without much difficulty.
	The second brass washer is put on last. Here are all the node details, in right order attached to the heating cable.
	All these parts are moved in a "package" close to the junction of the heating cable with the "cold end" - the power cable.
	The cable is inserted into the tee entry unit through the sleeve ...
	... and then stretches along its entire length - to the connecting node. In the example under consideration, in view of the fact that two 90-degree turns are assumed, we went along this path. Pushing a cable through even one perpendicular bend is a big and often insoluble problem. Trying to push it through two branches is simply useless. This means that the assembly of a complex section of pipes will be carried out with the simultaneous pulling of a heating cable through it.
	We go directly to the place where the water supply is assembled - to the area where the pipe from the heated room goes down into the well. Here is the first vertical section, which passes through a branch into a horizontal one. The tee is “packed” onto the pipe section, so that the cable entry is on top. The cable is pushed forward - it was introduced into the first turn zone in advance.
	We meet the cable at the end of the horizontal section and stretch it with a small margin.
	This is where the second 90 degree bend will stand, which will connect the horizontal section to the vertical pipe, which is already going into the well. To begin with, we simply drag the heating cable through the outlet.
	Only after that the fitting on the outlet is hermetically connected to the horizontal section of the pipe.
	The next step is to completely pull the heating cable through the outlet, so that the sleeve of its connection with the “cold end” is located right next to the input node.
	It turns out this is the picture - the cable is completely stretched, all the details of the input unit are assembled at the bushing.
	All parts of the assembly are alternately inserted into the through coupling. The rubber sealing sleeve must fit snugly - it must be forced down to the stop in order to open the threads for screwing in the compression nut.
	The nut is first tightened by hand, as far as possible ...
	... and then - pulled up with a key.
	Now it remains to fully assemble this heated section of the water supply.
	Through both existing turns, the cable is already pulled through, so no special problems are foreseen.
	The free end of the cable with a termination is inserted into a pipe descending into the well. The cable is quite rigid, and on a straight line vertical section the pipes will go down without any resistance.
	The cable goes deeper and deeper, and soon you can start installing the outlet on a vertical pipe.
	Everything, the transition node is assembled. The heating cable inside it will not allow water to freeze in the winter cold in this most vulnerable area of ​​\u200b\u200bthe water supply. Pay attention - the master additionally “dressed” the pipes in thin thermal insulation made of polyethylene foam.
	And this is the assembled unit for the passage of the heating cable into the pipe. If, after starting the system, there are signs of water leakage through it, it will be necessary to tighten the upper compression nut - the tightness will be restored, and the leak will disappear.

With all the advantages of this heating cable installation technology, it also has many disadvantages. The main ones are a decrease in the overall reliability of the plumbing system, as an extra tie-in point appears, a narrowing of the internal lumen of the pipe, and often difficulties when installing a cable in long or curved sections.

If this installation method is chosen, then it should be clarified in advance whether the heating cable has the appropriate certification for use specifically with drinking water.

Thermal insulation after laying the cable part

Heating the water supply with a cable will only make any sense if the subsequent thermal insulation of the pipes is provided.

• For these purposes, special materials are used, made in the form of half-cylinders or split cylinders, made of mineral wool, polystyrene foam, polyurethane foam, or rubber, other traditional thermal insulation materials with high thermal resistance.

• The installation of thermal insulation parts is recommended to be carried out immediately as the cable is laid - this reduces the possible risk of accidental damage. Before installation, make sure that the insulating material is completely dry, as the presence of moisture will significantly reduce its effectiveness.
• Installation of thermal insulation is carried out with the utmost care, so as not to damage the surface of the heating cable and not to shift its correct position on the pipe. All parts must be fixed in place and among themselves in the manner established for them. The joints, in the presence of cracks, should be caulked with mineral wool and glued with waterproof tape (if thermal insulation with an external foil coating is used, then the joints are glued with aluminum tape).
• In construction practice, it is customary to consider the following thicknesses of insulation for heated sections of water pipes:

- For diameters ½ and ¾ inch - 20 mm;

- Ø 1 and 1¼inch -30 mm;

— Ø 1inch—40 mm;

— Ø 2 inch—50 mm;

— Ø 2½ inch—65 mm.

• Having completed the installation of cylindrical parts of thermal insulation, we must not forget about their high-quality protection from moisture penetration from the end part.

After finishing the thermal insulation work, it will be possible to connect the heating system to the power supply and carry out a test run. If a thermoregulation system is installed, it is set to maintain the temperature in the pipe at a level of 3 - 5 ºС.

A well-planned and well-executed installation of a water supply heating system should, for a very long time, save the owner of the house from the “headache” regarding the water of possible freezing of pipes.

Read useful information in our new article, and flushing instructions.

Quite often in plumbing system needs repair due to freezing pipes in winter. To prevent accidents, heating is used through a cable installed inside or outside the pipe. Additional heating does not allow the pipelines to freeze, and it is easy to install with your own hands. The photo below shows how the heating cable is laid around the sewer pipe under insulation.

Heating cable around the pipe

Cable device

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

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

Scheme of the pipeline heating system with a 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 cables (green), junction boxes;
• control - protection equipment, start control, thermal control with air and pipe temperature sensors.

The heating cable is connected to the network by signals from temperature sensors. When the temperature of the environment rises (usually - more than 5 0 C), the cable is disconnected.

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

Advantages of cable heating:

• ease of implementation;
• the possibility of equipping any pipeline;
• economy and safety when done correctly.

Cable types

The most common is a 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 heating with your own hands, it can be successfully used. It is used for heating water pipes, sewer pipes, underfloor heating systems. Pipe diameter does not exceed 40 mm.

On fig. shown below are single-core (a) and two-core (b) resistive cables. The first is the cheapest and is best suited for do-it-yourself installation. The disadvantage is the need to return the wire to the voltage source for connection. For a two-wire wire, a sleeve is needed at the end.

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

Resistive wire is sold in a certain 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 tanks and pipes larger diameter self-regulating cables are used. They consist of two conductive wires. When voltage is connected 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 plastic depends on temperature environment, which provides significant energy savings due to self-regulation. Its price is an order of magnitude higher, and it is better to invite specialists for installation.

Plumbing with do-it-yourself protection

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

Heating cable outside

The depth of pipe laying is chosen according to the level of freezing 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 pavers being cleared of snow. In such places, the laying of pipes is made even lower, otherwise they will have to be constantly repaired due to freezing. The entry of the water supply may be close to the surface of the earth or pass through cold cellar. It is advisable to choose pipes from plastic, for example, HDPE. They are cheap and withstand repeated freezing.

In order not to frequently make repairs to replace pipes, it is advisable to lay a heating cable along with them in difficult areas. Buying an expensive heating system is not always justified. An alternative to it may be the use of an ordinary field worker for communication - P-274. It has a very strong insulation, which does not require replacement and repair for years in operation in field conditions. The presence of steel wires in the cores together with copper wires creates additional resistance, due to which the cable can be used for heating. On fig. below is a cross section of wire P-274.

Cross section of the field wire П-274

For safety, the P-274 field cable is not connected to a 220 V network. It requires a voltage of the order of 1-1.5 V per linear meter of cable. If we take it 30 m long, a voltage of 36 V is 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 made from a separate unit with a transformer.

For heating, you can even use a regular TRP telephone wire (fig. below). With it, you can also heat the fittings if the winding is made tighter.

Application of telephone wire for pipe heating

The field cable is wound on the outside of the pipeline in increments of about 10 cm (fig. below). Since it is cheap, you can wind another backup cable, since the next pipe repair will not be soon, but any homemade devices usually small. Two heaters can be connected at the same time in case of pipe freezing.

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

In regions with a cold climate, it is recommended to make the cable winding step more often. As a result, the heating efficiency is improved. 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 properly installed, it can work in all weather conditions, and it will not need repairs for a long time.

Application of the P-274 field cable for heating water pipes

When repairing water pipes, 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 soil.

In potentially dangerous places of the pipeline, 2-3 temperature sensors are installed. Soldering points are protected by heat shrink tubes with sealant. The temperature can be controlled automatically or manually.

The heating cable must be powered. 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 the inside

If it was not possible to install a heating cable when laying pipes, it can be placed inside an existing water supply system. Cable P-274 is resistant to water. A double wire can be untwisted and one core can be passed into the pipe, bending it in the middle. Then it is not necessary to strip 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. On fig. Below is a section of pipeline with a wire from the field cable 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.

The internal installation of the heater has the following disadvantages:

• reduction of the through hole;
• overgrowing of the conductor with a raid;
• the complexity of the plumbing scheme reduces its reliability.

Along with the disadvantages, there are also advantages:

• possibility of installation on the existing pipeline;
• little heat loss.

A flexible heating cable is preferably carried out on straight sections of the pipe or with small bends.

If the pipeline is rarely used, for example, in a country house, 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" one. In addition, it is necessary to reliably protect the conductors at the free end of the heater from moisture ingress with heat shrink tubes. The connection to the power cable is made through the lugs. The more reliable the connection, the less often the heating cable will need repairs.

Video about connection

How to connect a heating self-regulating cable with a termination kit can be found in the video below.

To prevent freezing of pipelines, special heating systems of varying complexity are used. To save money, you can install a heating cable with your own hands, for example, a telephone cable - P-274. The heating system can be made automatic with a thermal relay or with manual activation.

If the insulation is not sufficient to prevent freezing, a safe temperature must be maintained. They do this using a set of devices discussed in this article. The main functions are performed by a cable for heating. His right choice and application will help solve the problem without extra costs and difficulties.

Read in the article

How to use a special cable for heating a water pipe

Such solutions are used when it is impossible to obtain desired result with passive protection against the penetration of cold. Usually enough placement at a depth below the freezing level of the soil in a particular area. But the danger of ice plug formation occurs at the connection point to centralized systems.

This figure shows a diagram of a standard autonomous. Extreme fluctuations in temperature are often recorded in our time. In severe frost, freezing of the soil below the normal level is not ruled out. Particularly dangerous is the area of ​​exit from the ground and the entrance to the building. Here, even the high-quality modern insulation indicated in the drawing may not fulfill its functions.

It is easier to work with a two-core cable, since the electrical contact in it is created in the end part. In some products of this type, only one conductor is intended for heating.

The main advantage of such heaters is their relatively low cost. But there are also disadvantages that the future user should be aware of:

• The resistance cable for heating must be supplemented with a control device. using a special sensor, it detects a decrease in temperature below a certain level, turns the system on and off.
• Heating is carried out along the entire length of the conductor, regardless of the different levels of cooling of the hotel sections. It's not economical.
• A certain resistance is selected that provides the necessary heating at a supply voltage of 220 V. Therefore, an arbitrary change is impossible.

Self-regulating heater

This title is no exaggeration. Engineers really managed to create products that do not need to be used. external management.

The diagram shows the usual elements: copper conductors, shielding, resistant to high temperatures fluoroplastic insulation. But here the main useful function is performed by a special matrix. Its conductivity changes as the temperature increases/decreases. At the same time, there is a decrease / increase in heating.

These products are more expensive than resistive counterparts. However, they are much more economical to operate. When applied, the temperature will rise only where it is really needed.

Creating a heating system

The implementation of plans will be easier if you divide the entire project into stages:

• Preparation of drawings and list of components, tools, Supplies.
• Connecting heating elements to power wires.
• Mounting inside (outside) .
• Additional activities.

Connecting the heater and power cable: instructions

Below is an algorithm of actions and features that will be useful in practice:

Picture	Instructions
	Purchase a special kit designed for terminating self-regulating cables. It includes metal sleeves that create electrical connections. Useful with adhesive composition inside. When heated, they shrink, provide the necessary insulation, tightness.
	The cable is cut to size. Protective sheaths are removed from the attached end along a length of 40-50 mm. The semiconductor matrix is ​​neatly separated along the midline.
	Different tubes are put on these areas and heated with a hair dryer. This will later allow you to space the joints to improve the insulation parameters.
	Conductors are released from outer layers by 9-11 mm.
	They are inserted into the sleeves and rigidly fixed using wire cutters.
	The preparation of this part of the structure is completed by putting on tubes of a larger diameter (they do not need to be heated yet).
	Prepare the power cable in the same way. Remove insulation. Put on heat shrink tubing of suitable size.
	Wires in turn, taking into account different lengths, inserted into the sleeves, fixed with a clamp.
	The tubes are sequentially shifted and heated to obtain a multilayer reliable protection.
	Next, we proceed to isolate the other end. Remember that the conductors in it do not connect, since the current passes only through the matrix. To completely eliminate the possibility of contact, the cable is cut with a “step”.
	A heat shrink sleeve is put on top and heated. As a result, approximately such a product will be created.

Mounting outside the pipe

With this type of heater placement, for an approximate calculation required power use the following table:

For more precise actions, you can use the free ones that are offered on the official websites of sellers cable products. At the same time, specific operating conditions, liquid temperature, and installation features are taken into account. Experts do not recommend installing heaters with a power of more than 17 W per 1 m. plastic pipes. But in reality it is necessary to take into account the thermal stability a certain kind polymer. Towards metal products such restrictions do not apply.

Flat cables are better for this option. They adhere well to the surface, are easier to fix.

The cable is fixed with clamps resistant to high temperatures. The step is chosen in such a way as to exclude sagging. A protective casing is installed on top of the thermal insulation layer made of porous material, preventing its mechanical damage.

If necessary, increase the heat is added. It is advisable to place them in the lower part of the pipe, since it is there that undesirable icing processes begin.

Note! In some places, you can reduce the winding pitch, make a reverse turn to increase the heating area.

Installing a heating cable inside a plumbing pipe

This seems to be the preferred option. Inside the pipe, the product is well protected from mechanical influences. The heater is located inside the liquid, therefore, it performs its functions with maximum efficiency. This is confirmed by the numbers. To maintain a positive temperature, 8-10 W per 1 m of the track is quite enough. This figure is almost two times less compared to the previous (external) installation method.

But this technology can only be used in straight sections where there are no shutoff valves.

The piping design should include a 90° turn and fit a tee with the appropriate dimensions to accommodate the gland assembly.

Temperature control

Used to automate workflows. The device itself is installed in electrical panel. The temperature sensor is fixed on the pipe at the control point. It should be remembered that this element may fail over time, so it is installed in a place convenient for maintenance.

Important! The disadvantage of compact thermostats is the lack of adjustment and remoteness from the work area.

Connection to the electrical network for heating pipelines with a heating cable

The total power of the heating system can be significant. Therefore, it is connected to a 220 V network through a separate machine. It is also recommended to install a specialized protection device () in this circuit. It constantly measures the current. When fixing losses caused by insulation breakdown or touching a bare wire, the heater is quickly turned off.

thermal insulation

This operation is mandatory. It will prevent heat loss and prevent the penetration of cold. Air is the best insulator, so porous materials moisture resistant.

The water supply is installed in a special channel, which is formed by slabs of.

How much does it cost to install a heating cable for a water pipe outside the pipe: project price

To calculate the total costs, consider the following items:

• Purchase of a heater and power cable, thermostat, electrical safety devices.
• Preparation and installation of the product, connection to the power supply.
• Installation of insulation and mechanical protection.
• Purchase of solder and other consumables, tools as needed.

Such a project can be implemented without outside help, if you use the information provided in this article. To speed up - buy ready kit with cable for water pipe heating

Water pipes that lie at a shallow depth, as well as passing through unheated parts of the house, need to be heated. Otherwise, there is a risk of freezing of the water supply during periods of extreme cold and the cessation of water supply at home. To solve this problem, a special heating cable for plumbing is purchased, which is laid in a special way inside the pipes or wrapped around them. Manufacturers produce products of different lengths (from 2 to 20 meters or more), which allows heating only the part of the water supply system rising from the ground or the entire system located in the soil freezing zone.

How to prepare a heating cable for pipes for connection to a shield can be seen in the video. It also explains in detail how to insulate the second end of the electrical tape to prevent moisture from entering. All the necessary consumables and parts are included in a special kit, after unpacking it, they begin to prepare the cable for installation.

Self-regulating cable device

Self-regulating heating cable is available as a ribbon electric heater, whose parallel conductors are separated by a heat-generating semiconductor polymer matrix. An important feature of the matrix, which is the core of the heating cable, is the continuity of heating, which allows:

• to cut the cable in any right place without fear of cold zones;
• increase/decrease the amount of heat generated depending on the change in the temperature indicators of the external environment.

Each section of the self-heating cable is able to adapt to external conditions, and this does not affect the operation of its other parts in any way.

Due to the rationing of heat release for standardized conditions indicated in the name of the cable, the heating system cannot in practice overheat in principle. The presence of two layers of insulation allows the product to:

• dielectric strength;
• protection against abrasion and shock loads;
• moisture resistance;
• protection against exposure to chemical compounds.

It is important to note that a resistive cable for heating pipes is a quarter cheaper than self-regulating heating products, but they are more reliable and economical in operation. The fact is that a self-regulating cable can increase power when the temperature drops, and when it rises, it automatically turns off.

Scheme of a five-layer design of a heating cable: 1 - copper wires large section; 2 - self-regulating conductive material; 3 - modified polyolefin / fluoropolymer insulation (FS-C-2X); 4 - tinned copper braid for extra protection; 5 - outer insulation made of modified polyolefin

Choosing the type of cable and calculating its power

Installing a system to protect the water supply from interception and freezing allows you to lay pipes above the freezing level of the soil. In some cases, it is impossible to bury the pipeline deep into the ground for objective reasons. Pipes, additionally heated by an electric cable, need thermal insulation. This helps to reduce heat loss and economically use the potential of the heating element. Thickness thermal insulation material depends on the pipe diameter. The recommended values ​​of this parameter are given in the table:

The minimum thickness of the heat-insulating layer of the pipe, depending on its diameter

When selecting a heating cable and calculating power, take into account:

• water pipe diameter;
• the material from which the pipes are made;
• thickness of thermal insulation;
• heat losses of the pipeline, which must be completely blocked.

Features of installing a heating system inside the pipeline

This type of installation is chosen if the water pipes are already in operation and freeze in severe frosts. If a self-regulating heating cable is planned to be installed inside a drinking water pipe, then it is necessary to purchase a product that has a food suitability approval. The sheath of these cables is made of fluorine-containing polymer, which is tested for food safety. A gland is required to insert the heating cable into the pipe.

Installation of a self-regulating heating cable inside the pipe goes through the gland

If it is brought into the pipe from above, then fixing its position is not required. If the heating element is supplied from below, then to prevent it from slipping, reliable fixation is required.

To install a heating cable inside a pipe, it is necessary to accurately measure the length of the pipeline section that needs to be heated. It is forbidden to lay the heating cable through shut-off valves. The installation site of the water supply heating system is marked with a warning sign.

All actions when entering the cable into the pipe cavity must be carried out with special care and attention, since damage to its outer sheath cannot be allowed. It is better to close the threads on the fittings during installation with factory tape, like other sharp objects.

Methods for fixing the heating cable

1. Along the water pipe, one cable is laid in a straight line.

2. Unlike the first method, several cables are laid along the pipeline in a straight line, parallel to each other.

3. The laying of the electrical cable is carried out in a wavy line.

4. The cable for heating water pipes is wrapped around the pipeline in a spiral.

5. Several options for the location of the heating tape on individual elements of the pipeline (valves, elbows, flanges and other areas).

How to fix the heating cable over the pipe?

When installing the heating cable outside the pipeline, make sure that during operation there is no mechanical damage to the outer sheath (grinding, compression, crossing sharp edges, stretching). The electrical cable is tightly attached to the pipe with aluminum adhesive tape. It is strictly forbidden to use plastic tape instead of aluminum tape.

First attach the cable to metal pipe using separate pieces of aluminum tape, located at a distance of 30 cm from each other. Then, the same aluminum tape is passed over the cable along the entire length, which provides:

• lack of direct contact with the thermal insulation material;
• fastening strength to the pipe surface;
• large heat sink area.

Then, with the same aluminum tape, a sleeve is attached to the pipe, connecting the heating section to the supply wire equipped with a plug. The thermostat sensor is placed at an equal distance from the passing cable lines, secured with aluminum adhesive tape.

Important points to remember!

• Manufacturers advise mounting the heating cable on the elements of the water supply system at a temperature of minus 15 ° C and above.
• The minimum bending diameter of an electric cable is equal to the sum of six of its diameters.
• The pipeline heating system is supplied with a cable in without fail RCD (residual current device), which is selected in accordance with the PUE.
• After completing the installation work, check the resistance of the heating cable and insulation.

In addition to water pipes, this product is used for heating roofs, gutters, sewer pipes, etc. It is better to entrust the selection and installation of a cable to professionals who know all the nuances of such work.

Cable heating systems are special installations that, due to the current that produces the thermal effect that accumulates in special heating elements convert electrical energy into heat.

These systems in recent times have become very popular in many areas, for floor heating, heat preservation in pipelines, roof heating, for anti-icing of sidewalks, drains, driveways, heating of hardening concrete, for snowmelt of soil, greenhouses, steps, sports fields and so on.

The main advantage of cable heating systems is the small section of cables, because of this, the addition of these systems does not significantly change the dimensions of the structures in which they are installed.
https://www.youtube.com/watch?v=lk5XqC5IAxw
In addition, the installation of such systems is much easier than heating systems based on hot water, due to the fact that energy is also supplied to cable systems using thin cables, which are very easy to install.

Such a heating system is very, the energy loss in cable heating systems is much less, due to the fact that the supply cables are made with low resistance and the energy loss for heating them is very small.

A cable heating system consists of one or more pieces of cable, a thermostat and a temperature sensor.

The principle of operation of the cable heating system is the passage of current through the cable, this is what leads to heating of the wire.

The cable has a special sheath that can withstand constant heat, it also conducts heat very well, and this is what allows you to heat nearby various objects and space. Cables are also available in single or double strands. There are cables that are self-regulating and for them, unlike the first ones, thermostats with sensors are not required.

Cable heating systems during installation must be subjected to special calculations for more rational use. Also, if installed correctly, such a system will not overheat and will cost you much less than heating systems based on hot water.

According to their design, heating cables are divided into three types:

• resistive heating cable;
• self-regulating cable;
• zone heating cable.

Features resistive cable are its resistance and heating power, which practically do not change depending on the ambient temperature. Advantages include low starting currents and low cost. The disadvantages include the need for mandatory connection of temperature sensors and thermostats (to avoid overheating).

Self-regulating cable differs from resistive in its ability to reduce resistance as the ambient temperature rises. As a result, the heating power is reduced and energy savings are achieved. Its advantages, in addition to the cost-effectiveness of operation, include uniformity of heating, depending on local temperatures in different areas, greater safety (overheating and melting are excluded) and unpretentiousness during laying. The disadvantages are high starting currents and a high cost compared to a resistive cable, which eventually pays off.

Zone cable is a heating coil wrapped around conductive wires. Through contacts with conductors at certain intervals, independent heaters connected in parallel are formed. The advantages include low cost, ease of installation (as well as self-regulating, it can be cut off and installed directly on the site). The disadvantages are the same as those of a resistive cable.