Several cable accessories are used for effective functioning of the power distribution systems. Heat shrink tubes, power control cables, cold shrink tubes, busbar tubes, cable repair sleeve, cable end caps etc. are just to name a few of them. Among these, a brief on heat shrink tubing is given below.
Heat shrink tube as the name suggests is a shrinkable tube used for protecting wires from environmental stresses and abrasion. It is manufactured using sophisticated techniques and top quality materials. The materials normally used are nylon and polyolefin. Heat shrink tubing is available in standard size as well as customized ones. The tubing can function in temperatures of 125 C and some of them have a layer of thermoplastic adhesive which offers better adhesive power. It comes in different colour shades and this helps in colour-coding of wires and connections.
Heat shrink tubing is used for varied applications. The dimensions of the tubing required will depend on the kind and length of the cable and the type of tubing used. The following steps indicate the calculations that go to determine the quantity of heat shrink tubing required for any application.
- Compute the length of wire or cable
If a single or a part of a cable needs heat shrink then it is necessary to simply measure the length of the cable including the connector. The cable width also needs to be measured and both these figures can be arrived at through a tape measure or a ruler. If multiple wires are involved then they have to be kept adjacent to each other on some flat surface. They should be gathered together by wrapping an electrical tape around them after which the measurements can be taken in the above manner.
- Provide allowance in measurement for the heat shrinking
The calculation arrived at in the above step has to be increased by 25% to provide for the shrinkage that takes place during the heating. This will ensure that the tubing slides over the wires or cables with great ease.
- Addition to the length
An additional 10% has to be added to the tubing’s total length as calculated above. This needs to be done to accommodate the extra length of wire after the tubing shrinks.
- Know the various shrinkage ratios
The shrinkage ratios of different heat shrink tubes are different and it is essential to choose the one that best suits your requirements. The ratios are:
- 2-to-1 heat shrink tubing: The original diameter shrinks to 1/2 its size after being heated
- 3-to-1 heat shrink tubing: The original diameter shrinks to 1/3 its size after being heated
- 4-to-1 heat shrink tubing: The original diameter shrinks to 1/4 its size after being heated
It is essential to choose the heat shrink tubes carefully. If the tubing is very tight then it can damage the cable or wire and if it is too loose then it will not wrap tight around the cable or wire and will slip off. You can take the guidance of a reliable supplier so that you select the right type of heat shrink tubing.