3M™ Cold Shrink Connector Insulators (8420 Series)
Product overview
3M Cold Shrink Connector Insulators (8420 Series) are durable EPDM rubber tubes. They provide electrical insulation and waterproof sealing for cable connections rated up to 1000V. Factory-expanded onto a removable core, these cold shrink EPDM tubes contract around inline connectors and terminal lugs when the core is unwound. This tool-free installation requires no heat, torches, adhesives or additional coverings. Suitable for indoor and outdoor use, including direct burial and submersion, 3M 8420 insulators offer long-lasting protection against moisture, acids, alkalis, ozone and ultraviolet light.
3M Part Numbers: 8423-6, 8425-8, 8426-9, 8426-11, 8427-6, 8427-12, 8427-16, 8428-6, 8428-12, 8428-18, 8428-24, 8429-4, 8429-6, 8429-9, 8429-12, 8429-18, 8429-24, 8430-9, 8430-18, 8430-24.
3M™ Cold Shrink Connector Insulators (8420 Series)
Made from chloride- and sulphur-free EPDM rubber, 3M 8420 Series insulators provide electrical insulation and waterproof sealing for copper and aluminium cable connections. The cold shrink design maintains pressure around the connection, preventing water ingress while protecting against harsh environmental conditions. Suitable for solid dielectric rubber and plastic insulated cables, these insulators support a wide range of installation and repair applications.
Key Features & Benefits
- Insulates cable connections rated up to 1000V
- Accommodates a wide range of cable and connector sizes
- Factory-expanded EPDM rubber tube supplied on a removable core
- Installs quickly without tools, heat, torches, adhesives or additional coverings
- Provides a waterproof seal meeting ANSI C119.1 requirements
- Resists moisture, acids, alkalis, ozone and UV light
- Offers thermal stability and long-term elastic recovery
- Protects cable connections and terminal lugs
- Suitable for indoor, outdoor, overhead, direct burial and submerged use
- Compatible with copper and aluminium conductors in rubber or plastic insulated cables
- Made from chloride- and sulphur-free EPDM rubber
3M 8420 Series – Fast, Reliable Cable Insulation and Sealing
Made for electrical installation, maintenance and repair, 3M cold shrink insulators are suitable for inline power cable splices, secondary connections, terminal lugs and conductor transition connectors. They can also be used for sheath repairs, dig-in repairs and service relocations. The 3M 8420 Series offers a practical solution for applications where dependable insulation, moisture sealing and straightforward installation are essential.
For Additional Information on 3M Cold Shrink Connector Insulators (8420 Series), please consult the Technical Data Table or PDF File below.
*Technical Data subject to change without notice.
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+44 (0)1744 762 929Technical Data
PRODUCT SELECTION |
| Part No. | Min. Diameter (mm) | Max. Diameter (mm) | Length (mm) |
| 8423-6 | 7.8 | 14.3 | 152 |
| 8425-8 | 10.2 | 20.8 | 203 |
| 8426-9 | 13 | 25.4 | 229 |
| 8426-11 | 13 | 25.4 | 279 |
| 8427-6 | 17.5 | 33 | 152 |
| 8427-12 | 17.5 | 33 | 305 |
| 8427-16 | 17.5 | 33 | 406 |
| 8428-6 | 24 | 49.3 | 152 |
| 8428-12 | 24 | 49.3 | 305 |
| 8428-18 | 24 | 49.3 | 457 |
| 8428-24 | 24 | 49.3 | 609 |
| 8429-4 | 32.2 | 67.8 | 100 |
| 8429-6 | 32.2 | 67.8 | 152 |
| 8429-9 | 32.2 | 67.8 | 229 |
| 8429-12 | 32.2 | 67.8 | 305 |
| 8429-18 | 32.2 | 67.8 | 457 |
| 8429-24 | 32.2 | 67.8 | 610 |
| 8430-9 | 42.6 | 93.7 | 229 |
| 8430-18 | 42.6 | 93.7 | 457 |
| 8430-24 | 42.6 | 93.7 | 610 |
MATERIAL PROPERTIES |
| Test Methods | Typical Value |
| Colour | Black |
| 100% Modulus ASTM D 412 | 1.17 Mpa |
| 300% Modulus ASTM D 412-75 | 4.7 Mpa |
| Ultimate Tensile ASTM D 412-75 Original | 11.6 Mpa |
| Ultimate Elongation ASTM D 412-75 Original | 635% |
| Die C Tear ASTM D 624C-73 Original | 38.5KN/m |
| Shore A Hardness ASTM D 2240-75 | 48 |
| Permanent Set 3M Test Method @ 250% Strain 5 Minute Recovery | RT 8.8% 4.4°C (40°F) 14.6% |
| Moisture Absorption | Wt. Gain |
| 24hrs 90°C H₂O | 1.3% |
| 7 days 90°C H₂O | 3.2% |
ELECTRICAL PROPERTIES |
| Test Methods | Typical Value |
| Dielectric Strength ASTM D 149-75 Original @ 1.78mm | 19.1 MV/m |
| 7 days in H₂O at 90°C | 18.1MV/m |
| Dielectric Constant Original | 5.0 |
| 7 days 90°C H₂O | 5.6 |