Why do you need a heat shrink tube and how to use it?
Main purpose
The main purpose of heat shrinkage is to isolate live conductors. Thanks to its electrical insulation properties and easy installation, conventional insulation tapes can be successfully replaced.
At this time, it is easy to purchase heat shrink tubes in electrical goods stores that are used to protectwire connections. The popularity of this product as an insulating material lies in its ability to reduce its diameter due to high temperature. The required shrink temperature reaches 120 ° C. However, in order to do this, you need to know how to heat a heat-shrinkable tube. Thanks to heating, the heat shrink very tightly and reliably covers the insulated object, providing good insulation, as well as providing mechanical protection for the wires.
Manufacturers produce tubes of different sizes, and they are also color-coded. Due to this, they are used not only for good insulation, but also for further determination of the purpose of the insulated wire.
For example, for marking direct current wires, red is used for plus and black for minus. And for marking five-core electric cables, brown, white, black are used, which indicate phase conductors, zero is indicated in blue, grounding is yellow-green.
The use of HERE for marking the cable is quite convenient, because the heat shrink tube does not need to be pulled over the entire length of the wire. You only need to pull a small piece of heat shrink over insulation onto the end of the wire, as shown in the photo above. This marking is very reliable, and is not afraid of external influences, as well as temperature differences. Its service life is more than twenty years. This product is durable, inexpensive and very easy to use.
Advantages and disadvantages
If you compare shrinkage with other types of insulation, it has at least four advantages.
Firstly, since the heat-shrink tube fits very tightly, it does not move due to various mechanical influences.Secondly, the installation is a simple and quick process, but you still need to know some rules of use. Thirdly, after shrinkage, the insulation material becomes more durable, so the wire becomes even more resistant to mechanical damage and acquires additional rigidity at the junction. And the service life is much longer than that of conventional electrical tape. The fourth plus is a wide scope.
Of the disadvantages of the HERE tube, the following can be noted:
- It is impossible to reuse, because when it is heated, it changes its diameter, so it will be damaged when removed.
- The price of a heat-shrinkable tube is more than the price of electrical tape, but not so much that it becomes a decisive factor in choosing a protective and insulating material.
If any other shortcomings are found during use, then these are the shortcomings of the selected manufacturer.
The video below provides a clear comparison of heat shrink and electrical tape:
Where is the HERE tube used
Although the main task of the heat shrinkable tube is to isolate the contacts, there are other ways to use it:
- Isolation of water and metal pipes from an aggressive environment.
- Shrinkage on the butt of a metal or wooden support of power lines in order to protect against corrosion and decay of wood in the ground.
- Longitudinal sealing of cable bundles. Despite the external insulation, you can use a special tape that completely fills and also insulates the space between the cores of the wire.
- To improve the ergonomics of the handles of sports equipment and construction tools through the use of corrugated and ribbed surfaces of the tubes.
- Converting simple tools, such as screwdrivers into dielectric, using HERE isolation.
- Protect the wire from high temperature. There are products whose operating temperature range varies from -65 ° C to + 260 ° C. This protection helps the wire withstand such working conditions, even if there is a heat and fire source nearby. Such types of heat-shrinkable tubes are called fluoroplastic or teflon.
Shrink tube specifications
First you need to know what heat shrinkage for wires is made of. They make it from polymer, so it can change and shrink. The size of the tube HERE can be reduced by half or even six. The shrinkage coefficient of the product varies in the range from 2: 1 to 6: 1.
Also, heat shrinkings come with an adhesive layer, they are used when the joints need to be very reliably sealed to protect against moisture and corrosion. An adhesive layer achieves additional bond strength.
Heat shrinkable tubes differ in the composition of the polymer. Some are made from PVC, elastomers, polyolefins and various other materials. It is important that the product is resistant to fire, ultraviolet rays, as well as to have good mechanical properties.
It is also important to talk about the sizes of heat-shrinkable tubes. All manufacturers put a designation on the product that will indicate its dimensions. The diameter is indicated both before and after shrinkage. The first numbers indicate the internal size before shrinkage, and the next - either the diameter or the coefficient due to which it can be calculated. The basic or standard ratio is 2: 1. The maximum diameter of the TUT tube is 120 mm, and the minimum size is 2 mm before shrinkage.
The most necessary shrink sizes are provided in the table:
If you want to learn how to choose a shrink tube, we recommend watching the video below:
How to use heat shrink for wires
It remains to learn how to use a heat-shrinkable tube. So, you should first choose the appropriate shrink size. If needed insulate wires, then it is necessary to cut a suitable piece that would overlap the insulated area, taking into account that there will be longitudinal shrinkage when heated.Usually it is up to 10%, this information is indicated by the manufacturer. On the surface, as well as on the cuts of the cut tube, there should be no damage or any burrs, because they can contribute to the rapid destruction of the material.
First, the TUT tube is pulled onto the cable, and then you need to make a connection over which heat shrink will be worn. After joining, it must be heated with movements from one side to the other, so that large longitudinal shrinkage is not obtained. This can also be done by heating from the middle of the joint to the edges. The second method is applicable in fairly long sections.
It should be remembered that it is impossible to warm up simultaneously from both ends because an air bubble can remain, and this is very undesirable. Wrinkles may also appear on the surface. Heat shrink tube should be heated very carefully and evenly so as not to overheat in some place, because a bubble or tearing of the surface may appear.
The heating rate and temperature are determined by experience. However, one should not rush, especially if there is no experience in this direction. If heating is carried out too quickly, or at too high a temperature, this may damage the heat shrink.
The insulating process itself is not too complicated; if you wish, you can independently insulate the wire. However, for starters, you can experiment on some piece of wire and make sure that everything is done correctly, and after that take on the isolation of critical connections.
Finally, we recommend watching a video that clearly shows how to use a heat shrink tube for wires, using a hairdryer and a lighter for heating:
Now you know what a heat shrink tube is, why it is needed and how to use this device at home. We hope the information provided was informative and interesting for you!
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