Heating cable for water supply: how to choose and correctly install it yourself

In winter, during the period of severe frosts, the owners of country houses risk being left without water supply. Ice plugs in the external water supply will not only leave residents without a shower, an efficient system for supplying water to sinks and other benefits of civilization, but will also cause damage to pipes.

Agree, the prospect is unattractive. It will be possible to prevent such a development of events if, together with the pipes, a heating cable for the water supply system is installed and connected to the mains. All work is quite possible to carry out independently.

We will describe how the heating element is arranged and describe the main parameters for its selection. And also we will take a detailed look at the methods for installing a heating cable and illustrate the stages of work with visual photographs.

Why do I need a heating cable?

It is reasonable to argue that you can easily do without water heating. It is enough to find out the level of soil freezing in the area, and then, based on the indicators, dig a trench of the required depth. Usually it is 1.5-1.7 m for the middle strip, depending on the type of soil.

Buried and insulated pipes at this depth do not freeze, as the surrounding soil has a positive temperature (suppose + 2-4 ° C).

However, not all so simple. In wetlands or in areas close to water bodies, a frequent occurrence is a high level of groundwater. This means that during a flood or snowmelt, communications will be flooded, which will negatively affect their functional properties.

If you bury the pipes only half a meter, but at the same time connect the electric cable and make proper thermal insulationthen you won’t have to dig deep ditches.

It happens that in severe winters even deepened areas freeze. Living in a house without automatic water supply from the well becomes less comfortable, and sometimes impossible. We have to carry out emergency repairs

We will not forget about the critical zones most affected by the cold - the place where the pipeline enters the house. If the building is built on a pile-screw foundation, then under it is an open section of the pipeline, which is most easily insulated with a heating cable.

Conclusion: if there is a technical possibility of laying a heating system for a water supply system, you must definitely use it, at least for the sake of freezing.

When contacting a specialized company, you may come across some variety of offers. We will deal with the assortment.

Design and scope

Depending on the type and technical characteristics, heating cables are used to heat gutters, plumbing and sewer pipestanks. The main purpose is to protect the liquid from freezing by increasing the temperature.

Heating systems are relevant for outdoor communications, that is, for use in the ground or in the open air.

The basis of the operation is the ability of the cable to convert electricity to heat. The wire itself cannot transmit energy, as power analogs do. He only receives it, and then gives off heat to the pipe (tray, chute, tank, etc.)

Heating systems have one useful ability - zonal application. This means that you can take a set of elements and assemble from it a mini-system for heating an individual site, without connecting to the entire network.

It turns out saving materials and electricity. In practice, you can find miniature "heaters" of 15-20 cm, and 200-meter windings.

The main components of the heating cable are the following elements:

• Inner core - one or more. Alloys with a high electrical resistance are used for its manufacture. The higher it is, the greater the value of specific heat.
• Polymer protective shell. Together with plastic insulation, an aluminum screen or a copper wire mesh is used.
• Durable outer shell PVC covering all internal elements.

Proposals from different manufacturers may differ in nuances - core alloy or method of protection device.

More reliable are shielded species, equipped with foil protection and having 2-3 wires instead of one. Single-core products - a budget option, which is just right for assembling systems for small plumbing sections (+)

To improve performance, the copper braid is nickel-plated, and the thickness of the outer layer is increased. In addition, the PVC material must be moisture resistant and resistant to ultraviolet radiation.

Varieties of heating cable

All heating systems are divided into 2 large categories: resistive and self-regulating. Each species has its own field of application.

Suppose resistive ones are good for heating short pipe sections of small cross-section - up to 40 mm, and for long sections of water supply it is better to use self-regulating cable (in another way - self-regulating, “samreg”).

Type # 1 - Resistive

The principle of operation of the cable is simple: current flows through one or two cores located in the insulating winding, heating it. The maximum current strength and high resistance in total give a high coefficient of heat dissipation.

Pieces of a resistive cable of a certain length having constant resistance are commercially available. In the process of functioning, they give the same amount of heat over the entire length.

A single-core cable, as the name suggests, has one core, double insulation and external protection. A single core acts as a heating element

When installing the system, it must be remembered that a single-core cable is connected at both ends, as in the following diagram:

Schematically, a single-core connection resembles a loop: first it connects to an energy source, then it stretches (wraps) along the entire length of the pipe and returns

Closed heating circuits are more often used for heating the roof drainage system or for a “warm floor” device, but an option applicable to the water supply also exists.

A feature of mounting a single-core cable on a water pipe is laying it on both sides. Only the external connection type is used.

For core installation, one core is not suitable, since laying a “loop” will take up a lot of internal space, moreover, accidental crossing of wires is fraught with overheating.

The two-core cable is distinguished by the separation of core functions: one is responsible for heating, the second for energy supply.

The connection scheme is also different. There is no need for a “loop-shaped” installation: as a result, the cable is connected at one end to a power source, the second is drawn along the pipe

Two-core resistive cables are used for plumbing systems as actively as samregi. They can be mounted inside pipes using tees and gaskets.

The main plus of the resistive cable is its low cost. Many note reliability, long service life (up to 10-15 years), ease of installation.

But there are also disadvantages:

• high probability of overheating at the intersection or close location of two cables;
• fixed length - You can neither increase nor shorten;
• the impossibility of replacing a burned-out area - you have to change completely;
• lack of power adjustment - it is always the same along its entire length.

In order not to waste money on a permanent cable connection (which is impractical), a thermostat with sensors is installed. As soon as the temperature drops to + 2-3 ° C, it automatically starts heating, when the temperature rises to + 6-7 ° C, the energy is turned off.

Type # 2 - Self-Regulating

This type of cable is universal and can be used for various applications: heating roofing elements and water supply systems, sewer lines and containers with liquid.

Its peculiarity is independent adjustment of power and intensity of heat supply.As soon as the temperature drops below the control point (suppose + 3 ° C), the cable begins to heat up without any interference.

Scheme of self-regulating cable. The main difference from the resistive analogue is the conductive heating matrix, which is responsible for adjusting the heating temperature. Insulation layers do not differ

The principle of the samreg operation is based on the property of the conductor to decrease / increase the current strength depending on the resistance. With increasing resistance, the current decreases, which leads to a decrease in power.

What happens to the cable at the time of cooling? The resistance drops - the current increases - the heating process begins.

The advantage of self-regulatory models is the "zoning" of the work. The cable itself distributes its “labor”: it thoroughly warms up the cooling areas and maintains an optimum temperature where strong heating is not needed.

Self-regulating cable works constantly, and it is welcome in the cold season. However, during the thaw or in the spring, when the frost stops, keeping it turned on is irrational (+)

To fully automate the process of turning on / off the cable, you can equip the system with a thermostat that is “tied” to street temperature.

Installation methods for water supply

There are two ways to install the heating cable - external and internal. In the first case, it is attached along the pipe (or wound on it), in the second - it is wound inside. Both options have active practical application, so we will consider them more closely.

Option # 1 - Outdoor

Linear installation of the cable along the water pipe is easy. The wire is fixed on one side using high temperature-resistant plastic clamps or fiberglass self-adhesive.

The holders are fastened at intervals of 0.3 m. Do not use metal fasteners. It is not difficult to calculate the cable length - it is equal to the length of the pipe that needs to be heated.

Line Installation Instructions:

For pipes buried in the ground, the cable is not positioned strictly below or above, but slightly with an offset, which can be called the "position of 8 (4) hours."

In addition to the linear installation, spiral mounting is used - the cable is wound along the entire length of the pipe with a uniform pitch. Plus - maximum contact with the pipe surface, minus - increased material consumption.

The pitch between the turns can be changed depending on the conditions. For example, for areas subject to severe freezing, it is reduced - thus, the entire surface of the pipe will be warmed up as much as possible

The wound method is relevant for pipes of medium and large diameter - sewer, drainage, but it is also used for heating water pipes.

Option # 2 - Internal

The internal installation method is not suitable for all pipes, but only for water pipes with a cross section of more than 40 mm. In smaller pipelines, the cable will partially block the flow of water. It is difficult to equip a long pipe with internal heating, but for sections several meters long this is one of the best ways.

The easiest way to pull the cable in vertical sections is from top to bottom.The procedure involves the use of a tee and a sealing sleeve that prevents the cord from slipping.

In some cases internal cable installation more rational than external - for example, for repair or replacement of elements. It is not difficult to insert and connect a ready-made system, it is much more difficult to assemble it.

How to properly prepare the wires for entry into the pipe, you can learn from the following instructions.

Thermal insulation of heating cables

Regardless of the type of cable, it is necessary make insulation. Thermal insulation is mounted on top of the heating system and water pipe. If the water supply along with the heating cable is not placed in a sealed “cocoon”, the heating will go in all directions, that is, mostly in the air.

The thickness of the thermal insulation layer is selected depending on external factors. Assume that a 20-30 mm layer is sufficient for installation in the ground, while an aerial insulation of at least 50 mm in thickness is required for an overhead installation

As a reliable and effective insulation, expanded polystyrene or foamed polyethylene. They are resistant to moisture and create some protective cushioning for the pipe, but also need protection.

For this reason, the “pipe in pipe” design is often used when water pipes located in the ground or in the air, together with a heater, are placed inside another pipe of a larger diameter.

What characteristics are important to choose?

Before going to the store, be sure to check the diameter of the water pipe, the length of the area that needs heating, the lowest possible temperature of the air (soil) - it will be easier to make a choice, because there are really many offers.

So, we pay attention to the following points:

• the presence of a protective film - provides grounding and makes the cable more reliable;
• type of external insulation;
• temperature class and power;
• manufacturing company.

It is possible that a cable with a polyolefin insulation is suitable for a sewer system, but for internal installation in a water pipe we recommend fluoroplastic protection. For outdoor installation, a fluoropolymer is suitable, which will protect against moisture and ultraviolet radiation.

If it is necessary to heat pipes of small diameter, a low-temperature type conductor is suitable. It heats up to + 65 ºС, maximum power - about 15 W / m

Medium temperature systems are suitable for larger pipes. The maximum heating temperature is + 120 ° C, the power reaches 33 W / m.

The most powerful are high-temperature systems with a maximum temperature of up to + 190 ° C and a specific power of up to 95 W / m. However, they are usually not used in everyday life - these are products for industrial use.

Suitable power can be selected based on the diameter of the pipe.For example, for water pipes with a diameter of up to 2.5 cm, cables with a power of 10 W / m are suitable, from 2.5 cm to 4 cm - 16 W / m, from 4 to 6 cm - 24 W / m, etc.

There are several brands of heating cable, which have long established themselves only with the best hand.

Famous products of foreign companies:

• Nelson;
• Lavita;
• Devi;
• Ensto;
• Raychem.

Among Russian manufacturers, the company stands out FTA (Thermal Suite), producing high-quality household products.

Conclusions and useful video on the topic

The videos provide an opportunity to get acquainted with the practical application of the instructions.

Tips for installing a heating cable on a pipe:

Mounting option for screeds:

Instructions for connecting the cable inside the pipe:

The choice and installation of a heating system for a water supply system is even for a beginner. With the help of theoretical knowledge, you will quickly understand the types of cables, and for installation you do not need to master any special skills.

The result of the work may turn out to be worthy: you will forever forget about the problem of freezing water in the water supply system during the cold season.

Have experience installing a heating cable for autonomous water supply? Or maybe you want to share your impressions about using a heating element? Please share your opinion and leave comments.