Heat Shrinkable Anti-Tracking Breakouts
Heat shrinkable anti-tracking breakouts designed to seal and insulate cable crutch areas in multi-core medium-voltage cable terminations, while providing resistance to surface tracking, weathering, and environmental exposure.
Crutch Sealing for Medium-Voltage Cable Systems
Heat-shrinkable moulded breakouts applied at the crutch of multi-core MV cables — sealing the core separation point against moisture ingress and providing mechanical reinforcement at the transition between the cable body and individual cores. The adhesive inner lining activates during heat shrink, bonding to the cable surface without secondary application.
The anti-tracking (AT) compound suppresses carbonised surface path formation under combined electrical stress and environmental contamination — the primary failure mode at exposed MV crutch points. Suited for cable terminations and joints up to 36 kV in outdoor, polluted, and high-humidity environments.
- Material AT Crosslinked Polyolefin
- Voltage Up to 36 kV
- Shrink ratio 3:1
- Configurations 3-core, 4-core
- Flame retardant Yes — IEC 60332-1
- Halogen-free Yes
- Outdoor rated Yes
Why Anti-Tracking Breakouts Are Specified
Engineered for the specific failure modes and installation constraints of medium-voltage cable crutch applications.
Anti-Tracking Insulation
AT compound formulation actively suppresses the formation of carbonised surface paths under combined electrical stress and environmental contamination — the primary failure mode at MV cable crutch points.
Environmental Sealing
Hot-melt adhesive inner lining activates during heat shrink, bonding to the cable surface and forming a continuous seal against moisture ingress, water tracking, and environmental contaminants at the crutch.
Mechanical Reinforcement
Provides structural support and strain relief at the cable crutch, distributing mechanical stress across the core separation point and reducing the risk of insulation damage from movement or vibration.
Wide Cable Accommodation
A 3:1 shrink ratio accommodates a wide range of cable outer diameters and crutch dimensions within a single breakout size — reducing inventory requirement across mixed cable specifications on multi-cable projects.
Outdoor Durability
UV-stabilised, weather-resistant compound is formulated for direct outdoor exposure — including coastal, tropical, and industrially polluted environments where surface degradation rates are elevated.
Installation Efficiency
Single heat application completes the breakout seal — no secondary adhesive application, taping steps, or mechanical clamping required. Compatible with standard hot air gun or controlled flame torch.
Material & Performance Data
Reference data for engineering and procurement. Contact our technical team for full test reports or project-specific qualification data.
| Base material | Irradiation-crosslinked anti-tracking polyolefin (AT grade) |
|---|---|
| Colour | Red (standard) — custom colours available on request |
| Shrink ratio | 3:1 (recovered diameter : supplied diameter) |
| Voltage class | Up to 36 kV system voltage |
| Flame retardant | Yes — compliant with IEC 60332-1 |
| Halogen-free | Yes |
| Adhesive inner lining | Hot-melt thermoplastic adhesive — activates during heat shrink, no secondary application required |
| Installation method | Hot air gun (recommended) or controlled-flame propane / butane torch |
| Operating temperature | –55°C to +100°C (continuous service) |
| Core configurations | 3-core, 4-core |
| UV / weather resistance | Yes — UV-stabilised, outdoor rated |
| Applicable standards | IEC 60684 (heat-shrinkable tubing), IEC 60332-1 (flame retardance) |
Where Anti-Tracking Breakouts Are Used
Deployed in medium-voltage cable systems wherever crutch sealing, surface tracking resistance, and outdoor performance are required.
MV Cable Terminations
Primary application — MV cable termination systems up to 36 kV where crutch sealing and AT performance are mandatory requirements.
Underground Cable Joints
Sealing the core separation point in direct-buried or ducted cable joints, protecting the crutch against groundwater ingress.
Switchgear & RMU Connections
Cable entry sealing into ring main units and switchgear panels in outdoor and indoor MV distribution installations.
Transformer Terminations
Outdoor and indoor cable-to-transformer connections in distribution substations requiring long-term crutch integrity.
Outdoor Utility Installations
Direct-buried and above-ground cable terminations in power distribution networks exposed to weather and pollution conditions.
Railway Infrastructure
Traction power and signalling cable terminations in RDSO-compatible systems where outdoor AT performance is a specification requirement.
How to Select the Right Breakout
Six criteria determine the correct ATBR size and configuration for your application. Work through each in order before specifying.
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01
Voltage Class
Confirm the system voltage of the cable to be terminated or jointed. Western Cablex AT breakouts cover MV systems up to 36 kV. Specify the correct voltage class — an under-rated breakout is not acceptable in MV installations and must not be substituted.
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02
Number of Cores
Anti-tracking breakouts are available in 3-core and 4-core configurations. The core count defines the internal geometry of the breakout — confirm from the cable data sheet before ordering.
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03
Core Outer Diameter
Measure the outer diameter of each individual insulated core. This determines the finger bore size required. The breakout must recover tightly over the core insulation — oversized bore leads to voids at the adhesive interface.
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04
Crutch Dimension
Measure the overall cable outer diameter at the crutch — including any bedding layers or filler material present after armour termination. This determines the body diameter the breakout skirt must span and seal against.
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05
Indoor or Outdoor Installation
Anti-tracking grade is mandatory for all outdoor MV installations and strongly recommended for indoor MV switchgear connections. If the termination environment involves exposure to contamination, moisture, or elevated partial discharge conditions, specify AT grade regardless of whether the installation is classed as indoor.
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06
Colour Requirement
Standard ATBR colour is red. Some project specifications may require alternative colours for phase identification or system coding. Confirm colour requirements from the project specification before ordering.
If any dimension or specification is uncertain, contact our technical team before placing an order. Incorrect breakout sizing cannot be corrected on-site after installation begins.
Common Technical Questions
Anti-tracking refers to the material's ability to resist the formation of electrically conductive carbonised paths across its surface — a phenomenon known as surface tracking. When standard polyolefin is exposed to combined electrical stress and surface contamination (moisture, pollution, salt deposits), small leakage currents can gradually carbonise the surface, creating a conductive path that eventually causes flashover or insulation failure. The AT compound suppresses this process through its molecular formulation, making it resistant to surface erosion and carbonisation under these conditions.
Standard LV-grade breakouts are not suitable for medium-voltage cable systems. For systems operating above 1kV — and particularly for outdoor or exposed installations at 11kV and above — anti-tracking grade breakouts are required to maintain long-term dielectric integrity at the crutch. Using non-AT material in MV applications creates a surface tracking risk that may not manifest immediately but can lead to accelerated insulation failure over time.
The inner lining uses a thermoplastic hot-melt adhesive that is factory-applied to the bore of the breakout during manufacture. It activates automatically during the heat-shrink process — no separate adhesive application is required. The adhesive flows into surface irregularities as it melts, creating a continuous bond between the breakout and the cable surface. Ensure the cable surface is clean and dry before installation to achieve full adhesive contact.
A hot air gun is the recommended tool — it provides controlled, consistent heat distribution. A propane or butane torch with a spreading nozzle may also be used with care. Apply heat starting at the crutch body, working outward toward the fingers uniformly. Avoid directing concentrated heat at a single point, which risks scorching or uneven shrinkage. The breakout is fully recovered when adhesive is visibly flowing at the open ends and the surface is smooth, with no wrinkles or voids.
Service life is application-dependent and influenced by operating voltage, pollution level, thermal cycling, and UV exposure intensity. Western Cablex AT breakouts are stabilised for long-term outdoor use and are formulated consistent with the environmental ageing requirements of IEC and BS cable accessory standards. For critical infrastructure applications, consult our technical team for application-specific service life data.
Yes. The breakout is applied over the prepared cable cores after the armour has been terminated, the bedding cut back, and the crutch area prepared per the jointing kit instructions. The relevant dimension for breakout selection is the overall crutch diameter including any remaining bedding or filler material — not the armour outer diameter. Confirm this measurement from the prepared cable before selecting the breakout size.
Need help selecting the right anti-tracking breakout?
Speak with our technical team for sizing, application guidance, and product recommendations.