Why you can’t cut the heating cable? Can I cut the floor heating?

Resistance heating cables (floor heating) are sold in pre-cut sections connected to a power cold cable. Each section has a certain length and power. These are the values we use when calculating heating systems. But when an error creeps into the calculations and the rest of the cable has nowhere to mount, the first solution that seems logical is to cut off the excess.

The instructions that came with the heating sections prohibit any manipulation with shortening or extending the sections. Why? After all, in the catalogs the same heating cable, for example 20W/m, is sold in sections of 5m to 120m. And it seems that if we approach the case thoroughly, we can make quite a good end of the cable at home and use the rest of the cable somewhere else.

It is not for nothing that the manuals prohibit to cut the resistance heating cables. The thing is that in spite of the same article, heating sections of different lengths use different cables with different composition. For example the 10m and 20m sections, in their basis contain completely different heating cables. The manufacturer pre-calculates the resistance of the cable, setting at what length the heating power will be 20W/m. And if this cable is shortened by half, its power would increase by 2 times, which would make it 40W/m. Both the heating cores and the cable insulation are not designed for this kind of heat. When plugged in, such a cable will overheat and burn out. This is comparable to an incandescent filament in heating appliances. if it is shortened, it will glow to almost nothing and will quickly burn out.

In the case of local repairs of resistance heating cables in a screed, the damaged area must be replaced with a piece of heating cable from a similar section to prevent overheating in this area. A piece of cold connection cable must not be inserted as this would break the resistance of the remaining heating cable.

Resistive heating cable

Electric wire of resistive type for underfloor heating has one or two cores, which are placed in an insulating jacket, and at both ends there are sockets, with which the connection to the electric network is made. If you use a single wire under the screed, you need to ensure a closed circuit. This means that the cable should be placed on the floor so that both ends fit into the mounting box.

If a two-wire cable is used, the presence of a second conductor provides closure of the current circuit, so only one end is placed in the box, and a plug is mounted on the second.

Two-core cable has a more complex structure:

Two-wire heating cable for underfloor heating

  • both cores are placed in an insulating material, such as silicon rubber;
  • two wires are joined by glass fiber;
  • Tinned copper conductor is used for grounding;
  • The cores are protected from local overheating by aluminum foil;
  • The whole construction is encased in a PVC outer jacket.

Single-core cable has one significant advantage. the price, while double-core costs 20% more. Two-core is easy to lay under the screed. you can use any convenient method, without having to return the second end to the box.

A resistive wire is constantly releasing heat when connected to the mains. this is its main disadvantage. Because if the heat energy is blocked, it will cause the wire to overheat and short out. You should not lay these wires in places where you plan to put your furniture.

Which cable is better to use for underfloor heating: single core or twin core?

powerful heating is usually provided by double-wire heating elements. Depending on the time it takes to heat up the floor, the desired thermal microclimate will be adjusted. If there are no specific requirements to the temperature control you can use a single core heating cable.

Is it possible to shorten the temperature sensor cable for underfloor heating?? The standard wire length of remote temperature sensors is 2.5-3.5 meters The temperature sensor can be shortened without any problems.

floor, heating, cable

Self-regulating cable

Shielded or self-regulating cable for floor heating is a matrix, inside which are two conductors, and between them. a layer of polymer, which releases the necessary thermal energy. The peculiarity of this cable is that it controls the heating due to the resistance of the polymer. As the temperature rises, so does the resistance, which leads to lower amperage and therefore reduces the amount of heat produced.

Braided self-regulating heating cable

Shielded heating cable design

Despite the ability to control overheating, this cable is also not recommended to put under furniture, because it will increase energy consumption, but will not provide the necessary effect. it makes no sense to heat the cabinet.

Questions on installation and operation of the film floor

Question: Can I put heavy objects and furniture on the infrared film heated floor??

No, you can’t. And it’s not because of the increased weight load on the foil. In places where the film is pressed by a heavy load, it overheats locally, so some of the elements of the infrared heater may be destroyed.

It is also strongly not recommended to lay thick carpets or other items with heat-insulating properties on the film floor.

Question: Can I install infrared flooring under laminate, linoleum or carpeting??

You can use all of these types of flooring, you must strictly follow the instructions when installing. It is necessary to take into account that from the film floor, the laminate and other coatings will heat up. For laminate is normal, but linoleum or corolin will require some kind of gasket between the film and the coating, such as plywood.

Question: How to install radiant heat under laminate flooring? How to install a film floor under linoleum or carpeting?

The film floor under the laminate floor is quite easy to install. First, it is mandatory to mount the material that reflects the heat (for example, penofol) on the floor base. Its sheets for the convenience of fastening the usual scotch tape. The heating foil itself is placed on top of it.

Its contacts should be directed towards the point of installation of the thermostat. The thermostat can be connected to the socket using the plug supplied. The next stage of the work is to connect the wires to the film floor with special clips. At this stage it is necessary to monitor the electrical insulation. Before laying the laminate floor, the foil is covered with PE foil.

With linoleum or carpeting is somewhat more complicated. Linoleum should not be laid immediately on a warm floor. it will overheat and possibly warp. That is why the flooring under the linoleum is laid with several mm gaps between the sheets.

A PE film is laid on the foil floor, and then a rigid sheet of material, such as plywood, is added. This will not only level the floor, but also to protect it from damage. Fibreboard or OSB can be used, but is less preferable due to its rough surface. After leveling, a layer of linoleum (or carpeting) is laid and secured with mastic, and in its absence. with double-sided adhesive tape.

Also see below a video about installing infrared flooring.

Is it necessary to put a film on top of the infrared floor??

Manufacturers say in their materials that it is necessary to put polyethylene on top of the floor heating film. It acts as a protective covering for the film, which is especially important. If water can spill overhead. Some installers don’t do polyethylene, the floor won’t stop working. But the risk of damage and the danger of electrical short circuits increases many times. So it is better not to save money and put a polyethylene film on top of the infrared floor (see. (See also the video below)

Question: What happens if and how do you fix the heating foil??

floor, heating, cable

A foil floor is individual conductive elements connected in parallel with each other, so the entire floor cannot break down at once, even theoretically. If one of the elements breaks down, its functions will be shared by the remaining elements, so that such a breakdown does not lead to a change in the temperature in the room. The faulty module can be replaced during the next repair in the apartment.

likely the following faults: the temperature regulator has stopped working, poor connection or external influences (for example, jumping of children and adults on the floor) contacts in the places of wires connection to the foil were broken. In the first case, simply replace the thermostat. In the second case, you have to unscrew the floor itself to get to the contacts.

Question: What to do if there is a flooding emergency in the room where the underfloor heating is installed??

It is necessary to turn off the heating system. After that you need to carefully remove the water and wait until the floor is completely dry. It is impossible to use a film heated floor to dry wet surfaces.

Question: Can I do infrared film flooring in the bathroom??

In a bathroom or other room where there is a lot of moisture, it is better to do cable floor heating, in screed, or rod infrared flooring.

Question: What to do if the floor heating is locally overheated?

If the floor in one place is very (compared to the rest of the surface) heated, it may be a violation of electrical contacts. Most likely it will be in the places where the wires are connected to the foil. Disturbed contacts and excessive heat in this area are not good and not safe. The best thing to do is to take the laminate flooring apart, check and repair the contacts. Another factor confirming a break in contact could be a buzzing (humming like a transformer) in the place where the wires are connected to the foil, which will be heard when the floor is in heating mode.

Note: I must say that the surface of the floor (laminate or linoleum), under which the film is laid when it works warm. And here, as soon as the film runs out, the floor already feels cold (of course, in winter). So before you worry about localized overheating, take a good look, maybe you have a plnk ends/starts in this spot, and therefore it seems excessively warm here compared to the whole surface.

The most popular brands of heating cables and their characteristics

On the Russian market, represented as domestic manufacturers of electric cables for underfloor heating, and imported.

Mark Section length, m Power, W/m Maximum operating temperature, o C Service life, years
Single core cable
National Comfort, NK-250 17 15 90 15
Teprolux 10 14 90 25
Neoclima 5 15,2 100 35
Two-core cable
Ceilhit 8,1 18 100 25
Teprolux Elite 15 27 90 30
Raychem T2 14 20 100 35
Self-limiting cable
Optiheat 15/30 15 30 100 40
Devi-pipeguard 25 25 30 85 30
The heating mat
NeoClima 0,65 м 2 105 80 25
Electrolux EEFM 2 м 2 150 80 35
National Comfort 0,5 м 2 130 90 25
floor, heating, cable

Can the underfloor heating be repaired?

Only start a repair if enough cable is free. With the purchase of a complete set of floor heating, the consumer receives the necessary “little things” for its repair. special heat shrink sleeves and sleeves.

It is possible to cut a film floor. It can be cut using ordinary office scissors. Standard (striped) infrared flooring can only be cut along the cut line.

Can I shorten a floor heating cable?

The temperature regulator is an important element of any electric underfloor heating. It increases the efficiency of the entire system and significantly reduces energy consumption. The scheme of installation of this device is quite simple. Even a layman with basic electrical skills can install it.

A single-core heating cable for underfloor heating

How the thermostat works?

The main purpose of the thermostat is to maintain the stable operation of electric floor heating. Depending on the set parameters, it turns the heating elements on and off at certain times. This action allows you to reduce energy consumption without compromising the quality of heating. The temperature controller receives information about the system with a special sensor. It is installed inside the construction, where it registers changes in the specified temperature mode.

Connecting underfloor heating to a thermostat

There are the following varieties of devices to regulate the operation of the underfloor heating system:

Despite the difference in the structure of this type of devices, the scheme of their connection is not different.

Preparation work

Diagram of cable floor heating with thermostat

Before installing the thermostat, sensor and other elements of the system, it is necessary to make a calculation of the number of devices of this type, which will ensure the effective work of the underfloor heating. If the floor type of heating is provided for the whole house, then for each room it is recommended to make an independent connection to the mains.

Also for different circuits it is necessary to install a separate thermostat. This approach allows to get a more efficient system, where in each room you can set certain operating parameters.

Before installing the temperature controller, carefully inspect its enclosure and read the data sheet. Usually the manufacturer describes the installation diagram in detail. It should be understood that the power cable can be connected to the device either directly through the electrical wiring, or through a socket. Also manufacturers recommend additionally using a separate circuit breaker when mounting the thermostat. This will allow you to exploit the underfloor heating more effectively.

Temperature sensor installation for cable mats

The thermostat is installed on the wall near the electrical wiring. It is best to choose the place near the socket, but where there is no exposure to direct sunlight. Installation height of the thermostat is about 1.5 m. At the chosen site a small cavity is made, which will allow you to install the device box. It is also necessary to make a groove in the wall, where two plastic pipes will be placed.

They are designed for power wires heating cable and temperature sensor, which will be installed inside the structure of the underfloor heating. It is mandatory to connect the phase, ground and neutral conductors to the box of the thermostat. After all the preparatory work, proceed to install the single-core cable.

How to connect a cable floor heating to the thermostat

Installing a single-core cable

The scheme of installation of the main elements of the electric underfloor heating is as follows:

  • If necessary, the surface of the base is leveled.
  • A thermal insulating substrate with a foil coating is installed with the help of an adhesive tape. Installation of single-core heating cable, wiring diagram
  • The power cable is brought to the box of a thermo regulator. As a result, the connection sleeve should be inside the structure under the screed.
  • The adhesive tape is installed on the prepared base. It should be placed perpendicular to the coils of the electric cable floor heating and securely fix it.
  • A corrugated tube is installed between the coils of the cable, where the temperature sensor is mounted.
  • Use the tester to check the working resistance of the cable, which should not differ from the specified in the passport value by more than 10%. If everything is okay, the cement-sand screed is poured.

Connecting the system elements to the mains

After the temperature sensor is installed, you connect the floor heating to the temperature controller. The connection diagram of all the elements of the system is as follows:

The construction of the thermostat for underfloor heating

  • The first and second socket of the device is connected to the 220V power supply. The wiring diagram must be strictly followed. The wire L (phase) is connected to the first socket. It is mostly colored in white, black or brown. The N (zero) cable is connected to the second socket. It is marked in blue.
  • The cable-type floor heating is connected to the third and fourth socket. The connection scheme is as follows: the third socket is N (zero), the fourth is L (phase).
  • The fifth socket is for earthing installation. This cable is coloured green.
  • Connection of the temperature sensor is made to the sixth and seventh socket. The principle of polarity in this case does not need to be observed. Connect the sensor in any order. Diagram of connection of a single-core cable for underfloor heating
  • After connecting all the wires to the thermostat, they must be neatly tucked and the device must be placed in the ready-made box.
  • The temperature regulator should be adjusted to the correct position by using a spirit level. Only after that you can proceed to its fixation with the bolts that are included in the kit from the manufacturer.
  • The frame from the device is mounted on the ready made box. When it is in place, you can install the main part of the front panel. A characteristic click during installation will indicate that all has been done correctly.

After installation, check whether the temperature controller is operational. To do this, turn on the power and set the minimum operating temperature for the heating elements. To do this, there is a special button or handle on the device, depending on the specific model.

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