How To Install 3M Cold Shrink Cable Joints (LV)
Published 18 May 2018
A series of How-To videos for repairing, jointing and terminating cables using 3M Cold Shrink & Scotchcast products.
Cold Shrink Cable Joints
This video by 3M Electrical shows how to apply 3M Cold Shrink Cable Joints safely to splice, repair and connect low voltage power cables, 600V/1000V.
3M Cold Shrink cable joints utilise tool free cold shrink technology where no heat or gas torch is required for jointing cable in onshore and offshore locations with polymeric type cable insulation construction including both XLPE and EPR.
Cold shrink is an effective alternative to resin cable joints and can be used indoors, outdoors, overhead or used in cable trays.
Jointing Cables
Ensure all cables and conductors are free from dirt, residue and contaminants using cable cleaning wipes prior to preparing the cable to install the joint.
Cold shrink tubes and copper wire sleeves are first positioned over the cable.
The cable cores are then cut in such a way to stagger the position of the connectors – either mechanical shearbolt or crimp splice connectors are compatible. Check the proposed conductor connector is of suitable physical dimensions to be used with the cold shrink joint – on larger conductors due to volume displacement of multiple mechanical type connectors it maybe preferable for the jointer to use crimp/compression splices due to smooth profile design overcoming any potential bulging or distortion of the cold shrink tubes.
Accepted brands include Cembre, Arcus and Pfisterer Sicon type connectors.
The cable insulation is then removed and connectors are installed.
Most connector technology can be used providing they suit the requirements of the cable voltage, conductor construction and fit dimensionally within the 3M cable joint.
Scotch Electrical Tapes
Scotch 23 self-amalgamating tape is used to over tape the connectors. Layers of Scotch 23 are applied tightly around each connector overlapping into the primary insulation on each side of the connector position.
A piece of cable jacketing that has been saved from the cable preparation is then wrapped around the connectors for added mechanical protection.
Scotch 2228 mastic tape is then used to seal the crotch of the cable.
Scotch 33+ premium insulation tape is applied across the lengths of the cold shrink joint to improve electrical insulation and water sealing protection.
The copper wire sleeve is then repositioned over the joint and secured onto the cable armours (either wire or braid armour) with constant force springs providing a 360º earth screen around the cold shrink cable joint for added protection.
Scotch 23 self-amalgamating tape is used to tape over the constant force springs ensuring the application is in the same direction as the constant force springs.
Scotch 2228 mastic tape is wrapped over the constant force springs to ensure a smooth profile and to achieve the required cable seal.
The 3M cold shrink protection tube is then positioned over the cable joint. The coil is then removed by hand to install. The live memory action of the specially formulated material shrinks the cold tube into position and ensures a constant radial pressure and seal.
Cold Shrink Joints Selection Table For Power Cables
Selecting the correct 3M LC type cable joint for use with single and multi-core type power cables, typically BS5467 (SWA) or BS6883 (GSWB).Â
| Cold Shrink Joint Part Number | Cross Sectional Area (mm²) | Cable Diameter Range (mm) | Cable Armour Range (mm) | ||||
| Single Core 1kV | Two Core 1kV | Three Core 1kVÂ | Four Core 1kV | Three Core 3.3kV | |||
| 3M LC1 | N/A | 1.5 – 4 | 1.5 – 4 | 1.5 – 2.5 | N/A | 16.1 – 33.1 | 9 – 15 |
| 3M LC2 | 50 – 95 | 6 – 10 | 6 – 10 | 4 – 6 | N/A | 16.1 – 33.1 | 14 – 22 |
| 3M LC3 | 120 – 150 | 16 – 50 | 16 – 25 | 10 – 16 | N/A | 16.1 – 33.1 | 18.5 – 29 |
| 3M LC4 | 185 – 400 | 70 – 120 | 35 – 70 | 25 – 50 | 16 – 50 | 24.9 – 56.4 | 23.5 – 37 |
| 3M LC5 | 500 – 630 | 150 -185 | 95 – 150 | 70 – 120 | 70 – 150 | 37.8 – 84.3 | 31 – 50 |
| 3M LC6 | 800 – 1000 | 240 – 300 | 185 – 240 | 150 -185 | 185 – 240 | 37.8 – 84.3 | 44 – 70 |
| 3M LC7 | N/A | N/A | 300 | 240 – 300 | 300 | 62.5 – 128.5 | 44 – 70 |
Cold Shrink FAQs
Can 3M Cold Shrink Joints Be Resin Encapsulated?
Standard 3M Cold Shrink cable joints in the LC range can be over-protected by using cable joint moulds and then filled by pouring resin into the mould to encapsulate the joint – for example the cold shrink joint can be modified to provide resistance to hydrocarbon damage in hazardous area locations by using 3M Scotchcast 1402FR resin.
Can 3M Cold Shrink Joints Be Used To Joint Halogen Free & Flame Retardant Cables?
3M cold shrink joints can be used in conjunction with 3M STFF outer-protection sleeve – the joint sleeve is designed to protect the joint from fire. STFF sleeve is halogen free/zero halogen, flame retardant and does not emit toxic fumes in fire situations. Specified for onshore, offshore and rail tunnel applications where fire resistant protection of the cable joint is critical to overall performance, safety integrity and operational fire performance of the electrical cable and power system.
Can 3M Cold Shrink Be Used For Cable Repair?
Where cables have been subject to sheath degradation overtime due to electrical and mechanical stresses whilst in service a cold shrink tube can be used to re-instate the levels of cable insulation – note this requires access to an open-end of the cable or disconnection of the cable due to the tubular design of the cold shrink. If disconnection or isolation of the power cable system is not possible a heat shrink wrap-around type cable repair can be carried out. Read more about this subject in our detailed Blog covering solutions for repairing damaged cables.
Cold Shrink – invented by 3M over 40 years ago and now the preferred technology for heat-free jointing, terminating, sealing and abandonment of LV HV cables
We hope you find this video informative and educational, contact T&D for technical support, quotations and stock availability for 3M Low Voltage Cold Shrink Cable Joints.
âž¡ Visit 3M Electrical for further information about joints, terminations, tapes and insulation to seal, repair, splice and connect LV MV HV cables.
Learn more about the benefits and applications of Cold Shrink:
Cold Shrink | Joint | Terminate | Seal | Repair | Splice | LV MV HV Cables | 3M
- 3M Electrical Products Stocked By Thorne & Derrick InternationalÂ
