As a core component for cable insulation and sealing, the specification selection of EPDM cold-shrink tubes directly determines sealing reliability and service life. Correct selection must focus on "adapting to the target scenario + matching core parameters", combined with industry standards and actual application requirements, to achieve long-term stable protection effects.

Core Selection Logic: First Clarify Scenarios and Adaptation Objects

• Before selection, accurately locate the application scenario and covered object to avoid specification mismatch caused by basic information deviation: Clarify the application scenario: Distinguish between outdoor overhead, underground laying, communication base stations, power cables and other scenarios. Outdoor applications require enhanced weather resistance adaptation, while underground applications need to focus on wear resistance and waterproof sealing requirements.

• Confirm the covered object: Measure the maximum outer diameter, minimum outer diameter of the cable or joint, as well as the length of the joint to be covered, ensuring that the cold-shrink tube can fully and tightly wrap around it after shrinking.

• Clarify the operating environment: Mark the ambient temperature range, whether it is in contact with acid-base media, and whether it is long-term exposed to ultraviolet radiation, providing a basis for material performance parameter selection.

Key Specification Parameters: Core Indicators Determining Selection Success

1. Diameter Parameters: Dual Adaptation Before and After Shrinkage

• Expanded Inner Diameter: 2/3 of the maximum applicable size of the cold-shrink tube shall be greater than the maximum diameter of the covered object, ensuring that the support tube can be smoothly pulled out and fully sleeved into the joint.
• Recovered Inner Diameter: After shrinking, it shall be smaller than the minimum outer diameter of the covered object, achieving tight sealing by radial pressure to avoid loose gaps.
• Shrink Ratio: The general shrink ratio is 4:1. The larger the ratio, the wider the applicable cable diameter range and the stronger the versatility.

2. Length Specifications: Full Coverage + Reserved Margin

• Basic Length Requirement: It shall fully cover the cable joint, and overlap 20-50mm on the cable sheath on both sides of the joint respectively to ensure an unbroken seal.
• Reserved Length Margin: Considering the slight length reduction during the shrinking process, an additional 5%-10% length margin shall be added during selection.
• Scenario-based Adjustment: For long-term outdoor exposure scenarios, it is recommended to select longer specifications to enhance weather resistance protection effects.

3. Material Performance Parameters: Matching Environmental and Functional Requirements

• Operating Temperature: The temperature resistance range of conventional EPDM cold-shrink tubes is -40℃ to 90℃. The adaptability shall be confirmed according to the extreme ambient temperature to avoid low-temperature brittleness and cracking or high-temperature failure.
• Mechanical Properties: Tensile strength ≥8.6MPa, elongation at break ≥600%, ensuring sufficient toughness to resist mechanical damage during installation and use.
• Protective Properties: It shall meet the requirements of water resistance, ozone resistance, UV resistance and acid-base corrosion resistance. For outdoor scenarios, it is necessary to focus on verifying the compliance of UV aging and mold resistance tests.
• Electrical Properties: Dielectric strength ≥15kV/mm. When applied to medium and low voltage power cables, it is necessary to confirm that the insulation level meets the usage standard below 1KV.

4. Compliance and Adaptation Parameters

• Environmental Compliance: It shall comply with the EU RoHS directive to avoid excessive harmful substances affecting the safety of the application scenario.
• Installation Adaptability: Confirm that it can be installed manually without heating tools, and the support tube can be pulled out smoothly, which is suitable for on-site construction operation requirements.