FAQs: Medium and High Voltage Cable Accessories (5kV – 145kV)

3M™ Cold Shrink QT-II and QT-III Terminations function in a similar manner. They both employ 3M cold shrink technology which utilizes a high-dielectric constant (Hi-K) stress control tube. The Cold Shrink QT-II employs a dielectric grade silicone grease in conjunction with the stress control tube while the Cold Shrink QT-III employs a conformable Hi-K stress controlling compound. The termination is made from a pre-stretched Hi-K stress control tube and a silicone rubber termination insulator body installed around a core. When the core is removed, the rubber provides a constant inward pressure on the cable, forming a seal which expands and contracts with variations in temperature and load, thereby creating a ‘living seal.’

The silicone rubber material used to make the Cold Shrink QT-III termination has better track-resistant properties than the Cold Shrink QT-II, while allowing for a much shorter design without sacrificing product performance. This is especially important when space is in an issue as in cabinet placements. In addition, there are fewer steps involved when using a Cold Shrink QT-III termination so installation is simpler and generally quicker than the QT-ll termination.

Discover more about 3M Terminations for Electrical Construction and Maintenance.

Download brochures:
3M™ Cold Shrink QT-III Indoor and Outdoor Terminations (PDF, 1.17 MB)

No, unless the following conditions are met:
They are qualified as IEEE-48 Class 1 for indoor and weather-protected applications. For outdoor applications use one-piece, skirted silicone rubber terminations which meet IEEE-48 Class 1 for outdoor weather-exposed applications. Indoor terminations, such as the 3M™ Cold Shrink QT-III Silicone Rubber Indoor Tubular Termination Kits, 7640-T and 7650-T Series, can be specified for most outdoor, pad-mounted switchgear and transformer applications, since these enclosure interiors are protected from direct exposure to the elements.

Use the Medium Voltage Termination Kit Product Selector.

Yes. The 3M™ Cold Shrink Three Conductor Breakout Kit (3C-BOK Series) can be combined with your 3M™ Cold Shrink Single Conductor Accessories for 3 conductor applications. There are six 3C-BOK Kits in the series. Select the one that accommodates your cable dimensions, such as the cable insulation outer diameter (O.D.) (sometimes referred to as diameter over insulation) cable O.D., conductor size and insulation level (i.e., 100% or 133%).

3M™ Cold Shrink Three Conductor Breakout Kit 3C-BOK Brochure (PDF, 881.3 KB)

An inverted, skirted termination kit includes a non-skirted termination on one core and skirts on another core. The non-skirted termination is installed first and then the skirt assembly is installed on top of the non-skirted termination so that the skirts are oriented in the proper downward direction when the termination and cable are installed from the top direction versus the bottom direction, such as in a cabinet.

See a product example:
3M™ Cold Shrink QT-III Outdoor 4 Skirt Termination 7693-2-INV-4

Download a brochure:
3M™ Cold Shrink QT-III Indoor and Outdoor Terminations (PDF, 1.17 MB)

Yes, the 3M™ Cold Shrink Splice Kit 5550 Series Splice Kits are made to join non-shielded to shielded cable. These medium voltage splices allow you to splice 5/8 kV-rated power cables with aluminum or copper conductors. This kit is designed to splice tape shield, wire shield, UniShield® or non-shielded cables.

Our splice kits use EPDM* rubber which is designed to meet the continuous-current rating of the cable that the splice accommodates.

See the products:
3M™ Cold Shrink Rubber Splice Kit 5551, Tape, Wire, Unishield® 5/8kV

3M™ Cold Shrink Rubber Splice Kit 5552, Tape, Wire, Unishield® 5/8kV 4/0

Download the catalog:
3M™ Low and Medium Voltage Splice Kit catalog (PDF, 12.3 MB)

*ethylene propylene diene monomer rubber

Both splice families use the same molded silicone rubber splice body. The 3M™ Cold Shrink QS-III Splice Kit has two cores and the 3M™ Cold Shrink QS4 Splice Kit has a single core. The QS4 splice is integrated, making fewer steps and thereby reducing installation time. In the QS4 splice kits, all of the additional components are directly loaded on the splice body, including the shield sock and re-jacketing tube.

The Cold Shrink QS4 Splice features an Easy-Pulling Installation Core: The easier-unwinding, smooth edged yellow core provides for an installation of the splice with less effort. The Cold Shrink QS4 Splice’s integrated rejacketing eliminates the additional core that is used in Cold Shrink QS-III splice.

Download a brochures:
3M™ Cold Shrink QS4 Integrated Splice Kit (PDF, 845.5 KB)

3M™ Cold Shrink QS-III Splice Kit (PDF, 462.5 KB)

Our kits are designed to accommodate one feeder cable and one motor cable. If you have an application in which more than two cables are being connected, you will need to measure the approximate outside diameter (O.D.) of the cables you are using in your application and compare that to the inside diameter (I.D.) of the boot for the kit you are intending to use. Visit our product catalog for more information on 3M™ Motor Lead Connections and Kits.

Download catalog:
Motor Lead Connections (PDF, 1.3 MB).