Key features & benefits

Purpose-built stress grading - a single-layer semi-conductive sleeve that controls the field at the screen cut-back; no compromise on its one job.

Semi-conductive compound - volume resistivity ≥ 1×10¹⁰ Ω·cm: low enough to grade, high enough to insulate.

High-permittivity stress-control material - dielectric constant ≥ 15 (IEC 60250), the property that lets the sleeve capacitatively grade the field.

Medium-voltage rated - for cable terminations and joints up to 42 kV.

Wide continuous operating temperature - −40 °C to 100 °C for outdoor, buried and cold-climate service.

Tough, flexible wall - tensile strength ≥ 10 MPa, elongation at break ≥ 350 %.

Stable after heat ageing - tensile and elongation change ≤ ± 20 % after 130 °C × 168 h.

Consistent wall - low eccentricity (≤ 30 %) and longitudinal shrinkage (≤ 5 %) give a uniform, reliable stress-grading layer.

Controlled recovery - begins at 90 °C, fully recovered at 130 °C.

Black - the standard colour for semi-conductive / outer-screened components.

 

Applications

MV cable terminations up to 42 kV - stress control at the cut-back screen

MV cable joints up to 42 kV - field grading at the joint where the screen is removed

Stress-cone / stress-relief region of indoor and outdoor terminations

Joint kits and termination kits - supplied as the stress-grading sleeve component

XLPE, EPR and PILC screened cables - applied over the insulation at the screen edge

Field repairs and upgrades where the original stress-grading layer must be replaced

How this tube differs from the rest of the heat-shrink family

Tube	What it does	Nature	Volume resistivity	Colour	Size (as supplied → recovered)	When to choose it
WRSYL - Stress Control Tube (this page)	Grades the electric field at the screen cut-back	Single-layer semi-conductive	≥ 1×10¹⁰ Ω·cm	Black	Φ30–120 → 11–45 mm (12 specs)	Stress control on MV terminations & joints; the field-grading accessory
WDWT - Semi-conductive Dual Layer Tube	Re-insulates and re-screens the joint (rebuilds cable construction)	Dual layer: insulating inner + semi-conductive outer	Inner ≥ 1×10¹⁴ · outer ≥ 1×10¹⁰ Ω·cm	Red inner + black outer	Φ30–120 → 12–45 mm (8 specs)	You need the insulation wall and the outer screen in one sleeve
WRSJG - Anti-Tracking Insulation Tube	Resists surface tracking / flashover	Single-layer insulating	≥ 1×10¹⁴ Ω·cm	Red	Φ30–100 → 12–45 mm (14 specs)	Contaminated-env. terminations & busbars where tracking is the risk
WRSHG - Heat Shrink Protective Tube	Insulates, seals and armours (protection)	Single-layer, adhesive-lined both ends	≥ 1×10¹¹ Ω·cm	Black / red / yellow / blue / green	Φ10–300 → 5–100 mm (18 spec

Technical specifications

Selection table - standard sizes

Technical data

 

How to select the right size

Measure the diameter over the insulation at the screen cut-back region - the area to be stress-graded.

Pick by recovered ID - the recovered inner diameter must be slightly smaller than the substrate so the sleeve grips and bonds void-free. Example: a 20 mm insulated core → choose WRSYL-45/20 (as supplied 45 mm, recovers to 20 mm).

Check the as-supplied ID - the tube must slide over the largest part of the cone before shrinking (45 mm for a WRSYL-45/20).

Match the wall to the stress level - 2.0 mm walls (WRSYL-30/11 to WRSYL-45/20) for smaller terminations; 2.6–3.6 mm walls for larger, higher-stress joints and terminations.

Overlap into the screen - the sleeve should bridge from the intact screen across the cut-back and onto the insulation.

Choose length - standard cut lengths 100–1200 mm; continuous rolls 25 m (small specs) or 15 m (larger).

 

 

FAQ

Q: What is a heat shrink stress control tube used for? A: It controls (grades) the electrical stress at the screen cut-back of MV cable terminations and joints up to 42 kV. It is the semi-conductive sleeve that spreads the field so no single point is over-stressed - preventing partial discharge that would otherwise damage the insulation.

Q: Why is it semi-conductive? A: Its volume resistivity is ≥ 1×10¹⁰ Ω·cm - low enough to bleed off field concentration and grade the potential, but far too high to conduct. That is the defining property of a stress-grading material.

Q: How is it different from the semi-conductive dual layer tube (WDWT)? A: The dual layer tube rebuilds the cable - it supplies both an insulating inner layer and a semi-conductive outer screen in one sleeve. This stress control tube is a single-purpose field-grading accessory: it only grades the stress at the cut-back and does not replace the insulation or the outer screen. Choose WRSYL for stress grading, WDWT when the sleeve must also re-insulate and re-screen.

Q: What voltage is it rated for? A: MV cable terminations and joints up to 42 kV.

Q: What is the operating temperature? A: Continuous operation from −40 °C to 100 °C. Shrinking starts at 90 °C and the tube is fully recovered at 130 °C.

Q: What colour is it? A: Black - the standard colour for semi-conductive / outer-screened components.

Q: What sizes are available? A: 12 standard specs from WRSYL-30/11 (recovers to 11 mm ID) up to WRSYL-120/45 (recovers to 45 mm ID).

Q: How is it supplied? A: Standard cut lengths 100–1200 mm, or continuous rolls - 25 m/roll for smaller specs, 15 m/roll for larger. Custom lengths on request.