Smooth HDPE Standard Pipes Protection of electrical and telecommunication cables

NTET’s standard smooth HDPE pipes are designed for the protection of electrical and telecommunication cables in buried installations. Compliant with CEI EN 50626-1, they offer high resistance to compression and impacts, ensuring maximum protection even under dynamic loading conditions.

Available in 450 N class (SDR 17.6 / 17 / 13.6) and 750 N class (SDR 11 / 7.4), they cover nominal diameters from DN 40 to DN 250. Installation is carried out by trench excavation.

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Smooth HDPE Standard Pipes – Cable Protection

Resistance classes

The pipes are available in two compression resistance classes according to CEI EN 61386-24, each with different dimensional ratios (SDR).

Compression resistance ≥ 450 N at 23 °C. Available in SDR 17.6 — SDR 17 — SDR 13.6 ratios. Suitable for buried installations with moderate overlying loads.

Parameter Value Unit
Compression resistance ≥ 450N
Available SDRs 17,6 / 17 / 13,6
Nominal diameters 40 – 250 mm
HDPE density ≥ 0,932 g/cm³
Yield stress ≥ 19 N/mm²
Elastic modulus > 1000 MPa
Elongation at break ≥ 350 %
Surface resistance > 10¹² Ω
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Technical specifications

Material properties (HDPE)

  • Density: ≥ 0.932 g/cm³
  • Yield stress (23 °C): ≥ 19 N/mm²
  • Elastic modulus (23 °C): > 1000 MPa
  • Elongation at break (23 °C): ≥ 350%
  • Coefficient of linear thermal expansion: ~0.2 mm/m·K
  • Specific heat capacity: 2300–2900 J/kg·K
  • Thermal conductivity: ~ 0.4 W/m·K
  • Surface resistance: > 10¹² Ω

Dimensional table — Class 450 N

Dimensional ratios SDR 17.6 / SDR 17 / SDR 13.6:

DN (mm) Sn (mm) ID (mm)
50 3.0 44
63 3.6 55.8
75 4.3 66.4
90 5.2 79.6
110 6.3 97.4
125 7.1 110.8
140 8 124
160 9.1 141.8
180 10.3 159.4
200 11.4 177.2
225 12.8 199.4
250 14.2 221.6

Dimensional table — Class 750 N

Dimensional ratios SDR 11 / SDR 7.4:

DN (mm) Sn SDR 11 (mm) ID SDR 11 (mm) Sn SDR 7.4 (mm) ID SDR 7.4 (mm)
40 3.7 32.6 5.5 29
50 4.6 40.8 6.9 36.2
63 5.8 51.4 8.6 45.8
75 6.8 61.4 10.3 54.4
90 8.2 73.6 12.3 65.4
110 10 90 15.1 79.8
125 11.4 102.2 17.1 90.8
140 12.7 114.6 19.2 101.6
160 14.6 130.8 21.9 116.2
180 16.4 147.2 24.6 130.8
200 18.2 163.6 27.4 145.2
225 20.5 184 30.8 163.4
250 22.7 204.6 34.2 181.6

Jointing

Connections between pipes can be made by means of:

  • Butt welding for electrofusion
  • Mechanical jointing with simple and quick-to-use couplings, capable of ensuring maximum tightness

Reference standards

  • CEI EN 50626-1 — Specification for pipes for the protection of electrical and telecommunication cables
  • CEI EN 61386-24 — Compression resistance classification (450 N / 750 N)

Technical documentation

Scarica la scheda tecnica completa dei Tubi Lisci Standard HDPE per protezione cavi.

Applications

Designed for the protection of underground infrastructure in the electrical and telecommunications sectors.

  • Electrical cable protection

    Buried installation in trenches for the protection of low- and medium-voltage electrical lines. High compression resistance for overlying loads.

  • Telecommunication networks

    Duct for the buried installation of fibre optic and copper cables. Surface resistance > 10¹² Ω ensures complete electrical insulation.

  • Road and railway infrastructures

    Class 750 N for installations under roads or railways subject to intense dynamic stresses and heavy loads.

  • Crossings and urban utilities

    Trench installation for urban distribution networks. Quick jointing by welding or mechanical coupling.

FAQ

The classification refers to compression resistance according to CEI EN 61386-24. Class 450 N (SDR 17.6 / 17 / 13.6) is suitable for installations with moderate loads. Class 750 N (SDR 11 / 7.4) is intended for more demanding load conditions (under roads, railways, etc.).

SDR (Standard Dimension Ratio) is the ratio between the outside diameter and the wall thickness of the pipe. A lower SDR indicates a greater wall thickness and therefore higher compression resistance. For example, SDR 7.4 has a thicker wall than SDR 17.6.

Two methods: butt welding for electrofusion (permanent, high-tightness joint) or mechanical jointing with couplings, faster and suitable for sites where installation speed is required.

The range covers nominal diameters from DN 40 to DN 250 mm. Not all SDRs are available for all diameters: for example, SDR 17.6 starts from DN 50, while SDR 13.6 and the 750 N classes cover the full range from DN 40.

Yes. HDPE is naturally corrosion-resistant, resistant to chemicals present in the soil and to moisture. The high surface resistance (> 10¹² Ω) also ensures excellent electrical insulation.

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