Decoding Heat Shrink Tube Specifications - Inner Diameter or Outer Diameter

Publish Time: 11/30 2023 Author: Site Editor Visit: 96

What do heat shrink tube specifications mean?

Heat shrinkable tubes are divided into many types according to different properties and uses, and each type of heat shrinkable tube has many sizes. Insulating heat shrinkable tubes have more than 40 sizes. In this case, it is convenient to quote, produce and sell. Shrinkable tube manufacturers need to distinguish these sizes. For example, a φ2.0mm heat shrinkable tube is called a φ2.0mm specification. The heat shrinkable tube specification actually refers to the diameter size of the heat shrinkable tube.

In addition to expressing the diameter of the heat shrinkable tube specifications, the size of the folded diameter can also be measured. This method is often used when the diameter of the heat shrinkable tube is not known and there is no aperture gauge. First flatten the heat shrink tube, and then use a ruler to measure the width of the folded diameter. You can calculate the diameter of the heat shrink tube through a calculation formula. Diameter=(folding diameter*2)/3.14.

Soft flame retardant heat shrinkable tube specifications
Specification(mm)	Before shrinkage (mm)		After shrinkage(mm)		shape	Packing
Specification(mm)	the inside diameter of	wall thickness	the inside diameter of	wall thickness	shape	meters/roll
0.8	1.0±0.2	0.15	0.4	0.3	o	200
1.0	1.5±0.2	0.18	0.5	0.33	o	200
1.5	2.0±0.2	0.18	0.75	0.36	o	200
2.0	2.7±0.2	0.25	1	0.44	o	200
3.0	3.1±0.2	0.25	1.25	0.44	o	200
3.5	3.7±0.3	0.25	1.5	0.44	o	200
4.0	4.0±0.3	0.25	1.75	0.44	o	200
5.0	4.7±0.3	0.25	2	0.44	o	200
6.0	5.6±0.3	0.25	2.5	0.56	o	200
7.0	6.8±0.3	0.25	3	0.56	o	100
8.0	7.7±0.3	0.25	3.5	0.56	-	100
9.0	8.8±0.3	0.3	4	0.56	-	100
10	9.8±0.3	0.3	4.5	0.56	-	100
11	10.7±0.4	0.3	5	0.56	-	100
12	11.7±0.4	0.3	5.5	0.56	-	100
13	12.7±0.4	0.3	6	0.56	-	100
14	13.7±0.4	0.3	6.5	0.65	-	100
15	14.7±0.4	0.35	7	0.69	-	100
16	15.7±0.5	0.35	7.5	0.69	-	100
17	16.7±0.5	0.35	8	0.69	-	100
18	19.0±0.5	0.4	9	0.8	-	100
20	21.4±0.5	0.4	10	0.8	-	100
22	23.4±0.6	0.45	11	0.8	-	100
25	26.5±0.8	0.45	12.5	0.9	-	100
28	29.5±0.8	0.45	14	0.9	-	100
30	31.5±0.8	0.45	15	0.9	-	50
35	36.5±0.8	0.5	17.5	0.9	-	50
40	42.0±0.8	0.5	20	1	-	50
50	52.0±0.8	0.5	25	1	-	50
60	62.0±1.0	0.5	30	1	-	50
70	72.0±1.0	0.5	35	1.2	-	50
80	82.0±1.0	0.55	40	1.2	-	50
100	102	0.55	50	1.3	-	50
125	126	0.55	60	1.3	-	25
Remark:“o”Represents a round tube,“-”means flat tube,Special lengths can be cut

Does the heat shrink tube specification refer to the inner diameter or outer diameter?

The specifications of heat shrinkable tubes refer to the inner diameter. Except for PVC and PET heat shrinkable tubes, which are named according to the folding diameter, the specifications of heat shrinkable tubes made of other materials are named according to the inner diameter. Usually, the actual inner diameter of the heat shrink tube is slightly larger than the nominal inner diameter. For example, with the specification of φ2.0mm, the actual inner diameter of the heat shrinkable tube can reach about 2.5mm. The advantage of this is to improve the fault tolerance rate.

If the customer's wire diameter happens to be φ2.0mm, and then he also happens to choose a φ2.0mm heat shrink tube, it may not fit in, so the heat shrink tube manufacturer will make the actual inner diameter slightly larger than Nominal specification inner diameter, which can avoid a lot of unnecessary trouble.

There are still some users who cannot understand: Does the specification and model of heat shrink tube count as circumference or diameter? I can also tell you clearly here that the specifications and models of heat shrink tubes are diameter, not circumference.

Conclusion: The specification of the heat shrink tube is the inner diameter size of the heat shrink tube. The specification of the heat shrink tube refers to the inner diameter (diameter), not the circumference.